Pressure regulator

ABSTRACT

A main valve reduces an unregulated pressure of a high-pressure gas to a regulated pressure by being interlocked with a diaphragm, which receives the regulated pressure within a pressure regulating chamber and is displaced. A subsidiary valve is interlocked with the main valve through a plunger and reduces the unregulated pressure of the high-pressure gas to the regulated pressure. The subsidiary valve is located such that the force, which accompanies a pressure loss occurring at the subsidiary valve and which the subsidiary valve receives, cancels the force, which accompanies the pressure loss occurring at the main valve and acts upon the plunger. An adjustor adjusts a pressure loss value occurring at the subsidiary valve so as to be equal to the pressure loss value occurring at the main valve.

PRIORITY CLAIM

This is a continuation application of a co-pending U.S. patentapplication Ser. No. 10/788,348 filed Mar. 1, 2004, which claimspriority to Japanese applications serial nos. 055453/2003, 114260/2003,and 132876/2003 filed Mar. 3, 2003, Apr. 18, 2003, and May 12, 2003,respectively.

INCORPORATION BY REFERENCE

The U.S. patent application Ser. No. 10/788,348 filed Mar. 1, 2004 ishereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a pressure regulator for reducing anunregulated pressure of an introduced high-pressure gas and obtaining apredetermined regulated pressure, which pressure regulator is suitablefor use in liquefied gas utilizing appliances, gas supply facilities,and the like, and particularly for stabilization of fuel supply to solidoxide type fuel cells (SOFC's) and solid polymer type fuel cells(PEFC's).

2. Description of the Related Art

Ordinarily, liquefied gases and ordinary high-pressure gases, which havebeen accommodated in, for example, gas cylinders, have very highunregulated pressures and cannot be utilized directly. Also, theunregulated pressures of the liquefied gases and the ordinaryhigh-pressure gases fluctuate markedly due to factors, such as anambient temperature and a residual gas quantity. Therefore, pressureregulators (or pressure governors) for reducing the pressures of thehigh-pressure gases have heretofore been utilized widely in liquefiedgas utilizing appliances, gas supply facilities, and the like. Thepressure regulators have structures, wherein a regulated pressure isdetected by a diaphragm, a regulating valve capable of moving inaccordance with a displacement of the diaphragm is operated such thatthe regulated pressure becomes equal to a predetermined pressure incases where the unregulated pressure fluctuates, and the predeterminedregulated pressure is thereby obtained. (A pressure regulator having thestructure described above is described in, for example, PatentLiterature 1.)

The pressure regulators having various structures designed in accordancewith required operating ranges of unregulated pressures, requiredresponse characteristics, and required stability have been used inpractice. In accordance with the quality required of the regulatedpressure, one kind of a pressure regulator or a combination of severalkinds of pressure regulators has heretofore been used, and thepredetermined regulated pressure has thus been obtained.

Fundamental structures of ordinary pressure regulators will be describedhereinbelow with reference to FIGS. 15A, 15B, and 15C. FIGS. 15A, 15B,and 15C are schematic views showing fundamental structures of ordinarypressure regulators. FIG. 15A is a schematic view showing a single-valvetype pressure regulator. With reference to FIG. 15A, a pressureregulator 500 comprises a diaphragm 504, which partitions a regionwithin a casing 501 into a pressure regulating chamber 502 and anatmospheric chamber 503. The pressure regulator 500 also comprises a gasintroducing port 505, through which a high-pressure gas having apressure before being regulated is introduced into the pressureregulator 500. The pressure regulator 500 further comprises a regulatingvalve 506, which is interlocked with the diaphragm 504. The regulatingvalve 506 opens and closes an aperture 506 c, through which the gasintroducing port 505 and the pressure regulating chamber 502 communicatewith each other. The regulating valve 506 performs the operations foropening and closing the aperture 506 c from the unregulated pressureside and thereby reduces and regulates the unregulated pressure to theregulated pressure. The pressure regulator 500 still further comprises agas discharging port 508, through which the gas having the regulatedpressure and having passed through the pressure regulating chamber 502is discharged. The pressure regulator 500 also comprises a weight 509,which urges the diaphragm 504 toward the direction of opening of theregulating valve 506 and thereby sets the regulated pressure.

The pressure regulator 500 is based upon the detection of a pressuredifference between the atmospheric pressure and the regulated pressure.Specifically, the force occurring from an area of the diaphragm 504 andthe pressure difference between the atmospheric pressure and theregulated pressure acts toward the direction of closing of theregulating valve 506, and the gravity of the weight 509 acts toward thedirection of opening of the regulating valve 506. In a state in whichthe force occurring from the area of the diaphragm 504 and the pressuredifference between the atmospheric pressure and the regulated pressureand the gravity of the weight 509 are balanced with each other, theregulated pressure is kept at the set pressure. In cases where thepressure on the gas discharging side, i.e. the regulated pressure in thepressure regulating chamber 502, is higher than the set pressure, thediaphragm 504 is displaced toward the side of the atmospheric chamber503, and the regulating valve 506 is operated in the direction thatcloses the aperture 506 c. In cases where the regulated pressure in thepressure regulating chamber 502 is lower than the set pressure, thediaphragm 504 is displaced toward the side of the pressure regulatingchamber 502, and the regulating valve 506 is operated in the directionthat opens the aperture 506 c. More specifically, the motion of thediaphragm 504 occurring from the detection of the aforesaid pressuredifference between the atmospheric pressure and the regulated pressureis transmitted to the regulating valve 506, which is located on the gasintroducing side, and the regulated pressure is kept at thepredetermined pressure through the pressure regulation performed withthe opening and closing operations of the regulating valve 506.

However, in the cases of the single-valve type pressure regulator 500described above, a pressure loss occurs due to the gas stream flowingthrough the regulating valve 506, and the force that displaces thediaphragm 504 toward the side of the atmospheric chamber 503, i.e. theforce acting in the direction that closes the regulating valve 506,arises excessively from the value of the pressure loss described aboveand the area of the regulating valve 506. As described above, theregulating valve 506 performs the operations for opening and closing theaperture 506 c from the unregulated pressure side. Therefore, in caseswhere the unregulated pressure becomes high, the aforesaid excessiveforce acting in the direction that closes the regulating valve 506becomes large. Accordingly, the problems occur in that, as theunregulated pressure becomes high, the regulated pressure becomes lowlittle by little, and the gas stream is ceased with the passage of time.

FIG. 15B is a schematic view showing a duplex-valve type pressureregulator. With reference to FIG. 15B, a pressure regulator 600comprises a diaphragm 604, which partitions a region within a casing 601into a pressure regulating chamber 602 and an atmospheric chamber 603.The pressure regulator 600 also comprises a gas introducing port 605,through which a high-pressure gas having a pressure before beingregulated is introduced into the pressure regulator 600. The pressureregulator 600 further comprises two regulating valves 606 and 607, whichare interlocked with the diaphragm 604. The regulating valves 606 and607 respectively open and close two apertures 606 c and 607 c, throughwhich the gas introducing port 605 and the pressure regulating chamber602 communicate with each other. The regulating valves 606 and 607 thusreduce and regulate the unregulated pressure to the regulated pressure.The pressure regulator 600 still further comprises a gas dischargingport 608, through which the gas having the regulated pressure and havingpassed through the pressure regulating chamber 602 is discharged. Thepressure regulator 600 also comprises a weight 609, which urges thediaphragm 604 toward the direction of opening of the regulating valve606 and thereby sets the regulated pressure.

The two regulating valves 606 and 607 described above are located suchthat the regulating valve 606 performs the operations for opening andclosing the aperture 606 c, which communicates with the pressureregulating chamber 602, from the unregulated pressure side, and suchthat the regulating valve 607 performs the operations for opening andclosing the aperture 607 c from the regulated pressure side. Therefore,with the duplex-valve type pressure regulator 600, the force due to thepressure loss occurring at the regulating valve 606 and the force due tothe pressure loss occurring at the regulating valve 607 act in reversedirections and cancel each other. Accordingly, the drop of the regulatedpressure accompanying the increase in the unregulated pressure iscapable of being compensated for, and the regulated pressure is capableof being kept at a predetermined pressure.

As described above, the duplex-valve type pressure regulator 600 hasgood performance. However, the duplex-valve type pressure regulator 600has the problems in that the two regulating valves 606 and 607 cannotalways be located appropriately. Even if the two regulating valves 606and 607 are capable of being located such that the regulating valves 606and 607 simultaneously come into contact with their valve seats, thepressure loss of the gas stream passing through the regulating valve 606and the pressure loss of the gas stream passing through the regulatingvalve 607 cannot always be equal to each other. Therefore, it is notalways possible to constitute the duplex-valve type pressure regulator600 such that the force exerted by the unregulated pressure upon theregulating valve 606 and the force exerted by the unregulated pressureupon the regulating valve 607 are perfectly canceled with each other.

FIG. 15C is a schematic view showing a modified duplex-valve typepressure regulator. With reference to FIG. 15C, a pressure regulator 700comprises a diaphragm 704, which partitions a region within a casing 701into a pressure regulating chamber 702 and an atmospheric chamber 703.The pressure regulator 700 also comprises a gas introducing port 705,through which a high-pressure gas having a pressure before beingregulated is introduced into the pressure regulator 700. The pressureregulator 700 further comprises a regulating valve 706, which isinterlocked with the diaphragm 704. The regulating valve 706 opens andcloses an aperture 706 c, through which the gas introducing port 705 andthe pressure regulating chamber 702 communicate with each other. Theregulating valve 706 thus reduces and regulates the unregulated pressureto the regulated pressure. The pressure regulator 700 still furthercomprises a regulating member 707, which is constituted of an O-ring andundergoes sliding movement together with the regulating valve 706. Thepressure regulator 700 also comprises a gas discharging port 708,through which the gas having the regulated pressure and having passedthrough the pressure regulating chamber 702 is discharged. The pressureregulator 700 further comprises a weight 709, which urges the diaphragm704 toward the direction of opening of the regulating valve 706 andthereby sets the regulated pressure.

The regulating valve 706 performs the operations for opening and closingthe aperture 706 c, which communicates with the pressure regulatingchamber 702, from the unregulated pressure side. The unregulatedpressure coming from the gas introducing port 705 acts upon one surfaceof the regulating member 707, which is constituted of the O-ring. Also,the regulated pressure, which comes from the pressure regulating chamber702 through an intra-plunger gas flow path 710, acts upon the othersurface of the regulating member 707. The force due to the pressuredifference between the unregulated pressure, which acts upon the onesurface of the regulating member 707, and the regulated pressure, whichacts upon the other surface of the regulating member 707, is exertedupon the regulating member 707. The force, which is thus exerted uponthe regulating member 707, cancels the force occurring from the value ofthe pressure loss, which arises at the regulating valve 706, and thearea of the regulating valve 706. Therefore, even if the unregulatedpressure becomes high, the regulated pressure is capable of being keptat the predetermined pressure. With the modified duplex-valve typepressure regulator 700, the regulating member 707 (corresponding to theregulating valve 607 of the duplex-valve type pressure regulator 600shown in FIG. 15B) is constituted of the O-ring capable of undergoingthe sliding movement, and the problems with regard to the location ofthe two regulating valves 606 and 607 of the duplex-valve type pressureregulator 600 shown in FIG. 15B are thereby solved.

[Patent Literature 1]

-   -   Japanese Unexamined Patent Publication No. 8(1996)-303773

As described above, the single-valve type pressure regulator has asimple structure, but has the problems in that the regulated pressurecannot always be obtained accurately with respect to a wide unregulatedpressure range. In order for the regulated pressure to be obtained withrespect to a wide unregulated pressure range by use of the single-valvetype pressure regulator, it is necessary that a plurality of thesingle-valve type pressure regulators are utilized in order to reducethe unregulated pressure little by little from the high pressure to anintermediate pressure and from the intermediate pressure to a lowpressure. However, in such cases, the advantages of the single-valvetype pressure regulator with regard to the simple structure is lost.Also, in cases where the plurality of the single-valve type pressureregulators are connected to one another, it is necessary that the loadfor pressure regulation in the pressure regulator located on theupstream side, i.e. the pressure regulator for the high pressure, is setto be large. However, in such cases, follow-up characteristics withrespect to marked fluctuations in pressure cannot be kept good.

The duplex-valve type pressure regulator described above theoreticallyhas good performance. However, the duplex-valve type pressure regulatorhas the problems in that the two regulating valves cannot always belocated appropriately, and therefore the duplex-valve type pressureregulator cannot always be used in practice.

The modified duplex-valve type pressure regulator described above haspracticality, but has the problems described below. Specifically, sincethe value of the pressure loss occurring at the regulating valve variesin accordance with the gas flow rate, it is substantially impossible tocancel the force, which is exerted upon the regulating valve, by theforce, which is exerted upon the regulating member constituted of theO-ring. Therefore, an error in regulated pressure occurs in accordancewith the variation unregulated pressure. Also, since the regulatingmember (i.e., the O-ring) undergoes the sliding movement in accordancewith the variation in unregulated pressure, the frictional resistance atthe part of the regulating member is high. Therefore, the problems occurin that the response characteristics of the control of the regulatedpressure with respect to the variation in unregulated pressure cannot bekept good. As a result, the pressure regulation with respect to themarked variation in unregulated pressure cannot be kept quick, and thefluctuation in regulated pressure becomes large. In order to cope withthe problems described above, ordinarily, a lubricant is imparted to theO-ring sliding section. However, in cases where a gas having highdissolving characteristics is introduced into the modified duplex-valvetype pressure regulator, the lubricant is attached by the gas, and theresponse characteristics of the control of the regulated pressure withrespect to the variation in unregulated pressure quickly become bad.Therefore, the use of the lubricant is applicable only to the caseswhere an inert gas is introduced into the modified duplex-valve typepressure regulator.

Also, in cases where the pressure of the high-pressure gas is reducedand regulated with the pressure regulator provided with the diaphragm,it is desired that the pressure regulation to the regulated pressurehaving been set is capable of being performed accurately with respect toa wide unregulated pressure range. However, in cases where the regulatedpressure is set by the alteration of the pressure regulating loadapplied to the diaphragm, if the difference between the highest pressureof the unregulated pressure and the set pressure of the regulatedpressure is large, the problems will occur in that the accuracy withwhich the pressure is regulated becomes low.

Specifically, in cases where the degree of pressure reduction with oneregulating valve is high, the pressure fluctuation with respect to thefluctuation in degree of opening of the regulating valve becomes large.Therefore, the operation accuracy of the regulating valve and theproduction accuracy of the valve structure largely affect the accuracywith which the pressure is regulated. However, it is not always possibleto obtain a high operation accuracy of the regulating valve and a highproduction accuracy of the valve structure.

In view of the above circumstances, in one aspect of the presentinvention, as will be described later, two stages of governor means,i.e. a first-stage governor means comprising a diaphragm and aregulating valve and a second-stage governor means comprising adiaphragm and a regulating valve, are utilized, and the pressureregulation is performed in two stages in order for the pressureregulation accuracy to be enhanced. However, if two stages of governormeans are merely located in parallel, the problems will occur in thatthe size of the pressure regulator cannot be kept small.

Further, actually, the regulating valve performs the pressure reductionwith a very narrow valve space. Therefore, ordinarily, at least eitherone of the valve body and the valve seat of the regulating valve is madefrom an elastic body, such as a rubber material. However, in such cases,the problems occur in that various kinds of gases other than inert gasescause the elastic body to swell to a certain extent and to suffer from avariation in volume. The variation in volume of the elastic body arisesprincipally in the directions of opening and closing operations of theregulating valve. Therefore, the valve space between the valve body andthe valve seat becomes small with the passage of time of use, and theregulated pressure becomes low. In particular, in cases where a gashaving high dissolving characteristics, such as a dimethyl ether gas, isintroduced into the pressure regulator, it often occurs that the gasflow ceases within several tens of minutes.

Furthermore, in cases where a general-purpose synthetic resin isutilized as the material for a member constituting the pressureregulator, the problems described below occur. Specifically, when themember constituted of a certain kind of a general-purpose syntheticresin is brought into contact with the gas having the high dissolvingcharacteristics, such as a dimethyl ether gas, for a long period oftime, gas permeability, corrosion, cracks, and the like, occur with themember, and the member becomes not usable any more.

It is expected that dimethyl ether is usable as a substitute for aliquefied petroleum gas, a fuel for solid oxide type fuel cells(SOFC's), and a fuel for solid polymer type fuel cells (PEFC's).However, dimethyl ether exhibits a large variation in vapor pressurewith respect to temperature. For example, in cases where the temperatureof the use environment of at most 80° C. is taken into consideration,the vapor pressure of dimethyl ether rises to as high as 2,000 kPa. Incases where the pressure regulation is to be performed with respect tothe dimethyl ether gas, it is necessary that the pressure reduction andthe pressure regulation are capable of being performed sufficiently withrespect to the wide pressure range described above, and that thepressure regulator has a structure resistant to the dissolvingcharacteristics of the dimethyl ether gas.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a pressureregulator, wherein a mechanism for performing pressure regulation forobtaining a predetermined regulated pressure regardless of fluctuationin unregulated pressure of a high-pressure gas, particularly such thatthe unregulated pressure falling within a wide unregulated pressurerange from a low pressure to a high pressure is capable of beingregulated accurately to the predetermined regulated pressure, isconstituted of a small-sized, simple structure.

Another object of the present invention is to provide a pressureregulator, wherein a mechanism for performing pressure regulation forobtaining a predetermined regulated pressure regardless of fluctuationin unregulated pressure of a high-pressure gas, particularly such thatthe unregulated pressure falling within a wide unregulated pressurerange from a low pressure to a high pressure is capable of beingregulated accurately to the predetermined regulated pressure, and suchthat a sufficiently high follow-up speed is capable of being obtainedwith respect to a marked fluctuation in unregulated pressure of thehigh-pressure gas, is constituted of a small-sized, simple structure.

The specific object of the present invention is to provide a pressureregulator, which is capable of being used for a long period of time forregulation of pressure of a gas having high dissolving characteristics,such as a dimethyl ether gas.

The present invention provides a first pressure regulator, comprising:

i) a gas introducing port, through which a high-pressure gas having anunregulated pressure is introduced into the pressure regulator,

ii) a main regulating valve, which reduces the unregulated pressure ofthe high-pressure gas to a regulated pressure, a pressure loss occurringat the main regulating valve,

iii) a pressure regulating chamber for relaxing pressure vibration ofthe gas, which has passed through the main regulating valve,

iv) a diaphragm, which partitions off the pressure regulating chamberand an atmospheric chamber from each other, and which receives theregulated pressure within the pressure regulating chamber and is therebydisplaced,

v) a plunger, which interlocks the diaphragm and the main regulatingvalve with each other,

vi) a pressure setting section for adjusting a quantity of thedisplacement of the diaphragm,

vii) a gas discharging port, through which the gas having the regulatedpressure is discharged from the pressure regulator,

viii) a subsidiary regulating valve, which operates by being interlockedwith the main regulating valve through the plunger and which reduces theunregulated pressure of the high-pressure gas to the regulated pressure,a pressure loss occurring at the subsidiary regulating valve, thesubsidiary regulating valve being located such that the force, whichaccompanies the pressure loss occurring at the subsidiary regulatingvalve and which the subsidiary regulating valve receives, cancels theforce, which accompanies the pressure loss occurring at the mainregulating valve and which acts upon the plunger, and

ix) adjustment means, which is capable of adjusting a value of thepressure loss occurring at the subsidiary regulating valve,

the adjustment means being adjusted such that the value of the pressureloss, which the main regulating valve receives, and the value of thepressure loss, which the subsidiary regulating valve receives, becomeequal to each other.

The first pressure regulator in accordance with the present inventionshould preferably be modified such that a valve body of the mainregulating valve and a valve body of the subsidiary regulating valve arelocated on the plunger,

one of the two valve bodies is located on the unregulated pressure side,and

the other valve body is located on the regulated pressure side.

Also, the first pressure regulator in accordance with the presentinvention should preferably be modified such that the adjustment meansis capable of adjusting the value of the pressure loss, which occurs atthe subsidiary regulating valve, with an operation for varying aposition of a valve seat of the subsidiary regulating valve with respectto a movement of the plunger.

Further, the first pressure regulator in accordance with the presentinvention should preferably be modified such that the adjustment meansis constituted of a duplex-valve adjustor provided with:

an aperture region, which is fitted for sliding movement onto a part ofthe plunger, the part being located between the valve body of the mainregulating valve and the valve body of the subsidiary regulating valve,and

the valve seat of the subsidiary regulating valve.

In such cases, the first pressure regulator in accordance with thepresent invention should preferably be modified such that the gasdischarging port is formed through the duplex-valve adjustor. Also, thefirst pressure regulator in accordance with the present invention shouldpreferably be modified such that the gas having the regulated pressurewithin the pressure regulating chamber passes through a secondary gasflow path extending through a center area of the plunger and thuscommunicates with the gas discharging port.

Furthermore, the first pressure regulator in accordance with the presentinvention should preferably be modified such that the pressure regulatorfurther comprises a valve closing spring, which urges the plunger towarda direction of closing of the main regulating valve.

Also, the first pressure regulator in accordance with the presentinvention should preferably be modified such that either one of thevalve body and the valve seat of the main regulating valve comprises anelastic body,

either one of the valve body and the valve seat of the subsidiaryregulating valve comprises an elastic body, and

each of the elastic body of the main regulating valve and the elasticbody of the subsidiary regulating valve is located in a state in whichthe elastic body is controlled such that the elastic body is preventedfrom deforming with respect to directions of valve opening and closingmovements.

Further, the first pressure regulator in accordance with the presentinvention should preferably modified such that each of the elastic bodyof the main regulating valve and the elastic body of the subsidiaryregulating valve is constituted of an O-ring.

The present invention also provides a second pressure regulator,comprising:

i) a gas introducing port, through which a high-pressure gas having anunregulated pressure is introduced into the pressure regulator,

ii) a main regulating valve, which performs gas pressure reduction to aregulated pressure, a pressure loss occurring at the main regulatingvalve,

iii) a pressure regulating chamber for relaxing pressure vibration ofthe gas, which has passed through the main regulating valve,

iv) a diaphragm, which partitions off the pressure regulating chamberand an atmospheric chamber from each other, and which receives theregulated pressure within the pressure regulating chamber and is therebydisplaced,

v) a plunger, which interlocks the diaphragm and the main regulatingvalve with each other,

vi) a pressure setting section for adjusting a quantity of thedisplacement of the diaphragm,

vii) a gas discharging port, through which the gas having the regulatedpressure is discharged from the pressure regulator, and

viii) a preliminary regulating valve, which operates by beinginterlocked with the main regulating valve through the plunger and whichreduces the unregulated pressure of the high-pressure gas from the gasintroducing port at a stage prior to the main regulating valve, apressure loss occurring at the preliminary regulating valve, the gas,which has a pressure having thus been reduced by the preliminaryregulating valve, being allowed to flow to the main regulating valve.

The second pressure regulator in accordance with the present inventionshould preferably be modified such that a valve body of the mainregulating valve and a valve body of the preliminary regulating valveare located on the plunger, and

the valve body of the preliminary regulating valve is located on the gasintroducing port side.

Also, the second pressure regulator in accordance with the presentinvention should preferably be modified such that the pressure regulatorfurther comprises adjustment means, which is capable of adjusting avalue of the pressure loss occurring at the preliminary regulatingvalve. Further, the second pressure regulator in accordance with thepresent invention should preferably be modified such that the adjustmentmeans is capable of adjusting the value of the pressure loss, whichoccurs at the preliminary regulating valve, with an operation forvarying a position of a valve seat of the preliminary regulating valvewith respect to a movement of the plunger.

Furthermore, the second pressure regulator in accordance with thepresent invention should preferably be modified such that the adjustmentmeans is constituted of an adjustor provided with:

an aperture region, which is fitted for sliding movement onto a part ofthe plunger, the part being located between the valve body of the mainregulating valve and the valve body of the preliminary regulating valve,and

the valve seat of the preliminary regulating valve.

In such cases, the second pressure regulator in accordance with thepresent invention should preferably be modified such that the gasintroducing port is formed through the adjustor.

Also, the second pressure regulator in accordance with the presentinvention should preferably be modified such that either one of thevalve body and the valve seat of the main regulating valve comprises anelastic body,

either one of the valve body and the valve seat of the preliminaryregulating valve comprises an elastic body, and

each of the elastic body of the main regulating valve and the elasticbody of the preliminary regulating valve is located in a state in whichthe elastic body is controlled such that a direction of swellingdeformation of the elastic body becomes different from directions ofvalve opening and closing operations.

Further, the second pressure regulator in accordance with the presentinvention should preferably be modified such that each of the elasticbody of the main regulating valve and the elastic body of thepreliminary regulating valve is constituted of an O-ring.

Each of the plunger, which links the main regulating valve and thepreliminary regulating valve with the diaphragm, and a supporter, whichreceives a pressure setting load acting upon the diaphragm, shouldpreferably be constituted of a light metal or a light metal alloy, suchas aluminum or duralumin. Alternatively, each of the plunger and thesupporter should preferably be constituted of a polyamide, a polyacetal,a polybutylene terephthalate, or a polypropylene, which is a crystallineresin. As another alternative, each of the plunger and the supportershould preferably be constituted of an acetal, a polycarbonate, oracrylonitrile-butadiene-styrene, which is a non-crystalline resin, thenon-crystalline resin having a surface coated with an epoxy resin or apolyamide resin.

Also, a casing in which the diaphragm is located should preferably beconstituted of a polyamide, a polyacetal, a polybutylene terephthalate,or a polypropylene, which is a crystalline resin. Alternatively, thecasing in which the diaphragm is located should preferably beconstituted of an acetal, a polycarbonate, oracrylonitrile-butadiene-styrene, which is a non-crystalline resin, thenon-crystalline resin having a surface coated with an epoxy resin or apolyamide resin.

The epoxy resin described above should preferably contain a polyphenoland epourea as principal constituents.

Also, the casing in which the diaphragm is located should preferably beconstituted of a polyamide, a polyacetal, a polybutylene terephthalate,or a polypropylene, which is a crystalline resin, and the casing shouldpreferably be formed with ultrasonic fusion bonding.

The present invention further provides a third pressure regulator,comprising:

i) a first-stage governor system, which is provided with a firstregulating valve for reducing an unregulated pressure of an introducedgas to an intermediate pressure, and

ii) a second-stage governor system, which is provided with a secondregulating valve for reducing the intermediate pressure to a regulatedpressure,

the first-stage governor system and the second-stage governor systembeing located such that a direction of displacement of a first diaphragmof the first-stage governor system, which first diaphragm operates thefirst regulating valve of the first-stage governor system, and thedirection of the displacement of a second diaphragm of the second-stagegovernor system, which second diaphragm operates the second regulatingvalve of the second-stage governor system, intersect with each other.

The third pressure regulator in accordance with the present inventionshould preferably be modified such that the first-stage governor systemcomprises:

a) a gas introducing port, through which a high-pressure gas having theunregulated pressure is introduced into the pressure regulator,

b) the first regulating valve, which reduces the unregulated pressure ofthe high-pressure gas within the gas introducing port to theintermediate pressure,

c) a first pressure regulating chamber for relaxing pressure vibrationof the gas, which has passed through the first regulating valve,

d) the first diaphragm, which partitions off the first pressureregulating chamber and an atmospheric chamber from each other, and whichreceives the intermediate pressure within the first pressure regulatingchamber and is thereby displaced,

e) a first plunger, whose one end is secured to the first diaphragm, avalve body of the first regulating valve being fitted to a region of thefirst plunger, which region is located in the vicinity of the other endof the first plunger, and

f) a first pressure setting section for adjusting a quantity of thedisplacement of the first diaphragm, and

the second-stage governor system comprises:

a) the second regulating valve for reducing the intermediate pressure ofthe gas, which has been introduced from the first pressure regulatingchamber, to the regulated pressure,

b) a second pressure regulating chamber for relaxing pressure vibrationof the gas, which has passed through the second regulating valve,

c) the second diaphragm, which partitions off the second pressureregulating chamber and an atmospheric chamber from each other, and whichreceives the regulated pressure within the second pressure regulatingchamber and is thereby displaced,

d) a second plunger, whose one end is secured to the second diaphragm, avalve body of the second regulating valve being fitted to a region ofthe second plunger, which region is located in the vicinity of the otherend of the second plunger,

e) a second pressure setting section for adjusting a quantity of thedisplacement of the second diaphragm, and

f) a gas discharging port, through which the gas having the regulatedpressure is discharged from the pressure regulator,

the first plunger and the second plunger being located such that thefirst plunger and the second plunger extend in directions whichintersect at right angles with each other,

a part of the second plunger being inserted for sliding movement into agas flow path extending from the first pressure regulating chamber tothe second pressure regulating chamber,

the second regulating valve being located within the first pressureregulating chamber.

Also, the third pressure regulator in accordance with the presentinvention should preferably be modified such that a pressure receivingarea of the first diaphragm of the first-stage governor system issmaller than the pressure receiving area of the second diaphragm of thesecond-stage governor system.

Further, the third pressure regulator in accordance with the presentinvention should preferably be modified such that either one of thevalve body and a valve seat of the first regulating valve comprises anelastic body,

either one of the valve body and a valve seat of the second regulatingvalve comprises an elastic body, and

each of the elastic body of the first regulating valve and the elasticbody of the second regulating valve is located in a state in which theelastic body is controlled such that a direction of swelling deformationof the elastic body becomes different from directions of valve openingand closing operations.

Furthermore, the third pressure regulator in accordance with the presentinvention should preferably be modified such that each of the elasticbody of the first regulating valve and the elastic body of the secondregulating valve is made from a urethane type rubber material. Also, thethird pressure regulator in accordance with the present invention shouldpreferably be modified such that each of the elastic body of the firstregulating valve and the elastic body of the second regulating valve isconstituted of an O-ring.

Each of the first plunger, which links the first regulating valve withthe first diaphragm in the first-stage governor system, the secondplunger, which links the second regulating valve with the seconddiaphragm in the second-stage governor system, a first supporter, whichreceives a pressure setting load acting upon the first diaphragm, and asecond supporter, which receives a pressure setting load acting upon thesecond diaphragm, should preferably be constituted of a light metal or alight metal alloy, such as aluminum or duralumin. Alternatively, each ofthe first plunger, the second plunger, the first supporter, and thesecond supporter should preferably be constituted of a polyamide, apolyacetal, a polybutylene terephthalate, or a polypropylene, which is acrystalline resin. As another alternative, each of the first plunger,the second plunger, the first supporter, and the second supporter shouldpreferably be constituted of an acetal, a polycarbonate, oracrylonitrile-butadiene-styrene, which is a non-crystalline resin, thenon-crystalline resin having a surface coated with an epoxy resin or apolyamide resin.

Also, a casing, in which the first-stage governor system and thesecond-stage governor system are located, should preferably beconstituted of a polyamide, a polyacetal, a polybutylene terephthalate,or a polypropylene, which is a crystalline resin. Alternatively, thecasing, in which the first-stage governor system and the second-stagegovernor system are located, should preferably be constituted of anacetal, a polycarbonate, or acrylonitrile-butadiene-styrene, which is anon-crystalline resin, the non-crystalline resin having a surface coatedwith an epoxy resin or a polyamide resin.

The epoxy resin described above should preferably contain a polyphenoland epourea as principal constituents.

Also, the casing, in which the first-stage governor system and thesecond-stage governor system are located, should preferably beconstituted of a polyamide, a polyacetal, a polybutylene terephthalate,or a polypropylene, which is a crystalline resin, and the casing shouldpreferably be formed with ultrasonic fusion bonding.

The first, second, and third pressure regulators in accordance with thepresent invention is also applicable in cases where the high-pressuregas is a dimethyl ether gas, which is utilized as a substitute for aliquefied petroleum gas, a fuel for solid oxide type fuel cells(SOFC's), and a fuel for solid polymer type fuel cells (PEFC's).

The first pressure regulator in accordance with the present inventioncomprises the main regulating valve, which reduces the unregulatedpressure of the high-pressure gas to the regulated pressure, thepressure loss occurring at the main regulating valve. The first pressureregulator in accordance with the present invention also comprises theplunger, which interlocks the main regulating valve and the diaphragmwith each other. The first pressure regulator in accordance with thepresent invention further comprises the subsidiary regulating valve,which operates by being interlocked with the main regulating valvethrough the plunger, and which reduces the unregulated pressure of thehigh-pressure gas to the regulated pressure, the pressure loss occurringat the subsidiary regulating valve. The subsidiary regulating valve islocated such that the force, which accompanies the pressure lossoccurring at the subsidiary regulating valve and which the subsidiaryregulating valve receives, cancels the force, which accompanies thepressure loss occurring at the main regulating valve and which acts uponthe plunger. The value of the pressure loss occurring at the subsidiaryregulating valve is adjusted by the adjustment means, such that thevalue of the pressure loss, which the main regulating valve receives,and the value of the pressure loss, which the subsidiary regulatingvalve receives, become equal to each other. Therefore, with the firstpressure regulator in accordance with the present invention, theregulated pressure is capable of being obtained accurately with respectto a wide unregulated pressure range by use of the one pressureregulator. Also, with the first pressure regulator in accordance withthe present invention, the location of the two regulating valves is easyto perform, and the constitution of the pressure regulator is capable ofbeing kept simple. Further, in cases where the value of the pressureloss occurring from the main regulating valve varies in accordance withthe gas flow rate, the force acting upon the main regulating valve iscapable of being accurately canceled by the subsidiary regulating valve,and the regulated pressure is capable of being kept at the predeterminedpressure regardless of the variation in unregulated pressure.Furthermore, in cases where the plunger moves with respect to thepressure variation, the resistance to the sliding movement of theplunger is low. Accordingly, the response characteristics of the controlof the regulated pressure with respect to the variation in unregulatedpressure is capable of being kept good, and the accuracy with which thepressure regulation is performed is capable of being kept high.

With the first pressure regulator in accordance with the presentinvention, wherein the pressure regulator further comprises the valveclosing spring, which urges the plunger toward the direction of closingof the main regulating valve, in cases where the set pressure of theregulated pressure is low, the accurate operation of the main regulatingvalve in accordance with the displacement of the diaphragm is capable ofbeing obtained, and reliable pressure regulation is capable of beingperformed. Also, a blocking state, in which the main regulating valveand the subsidiary regulating valve are closed, is capable of beingobtained reliably.

The first pressure regulator in accordance with the present inventionmay be modified such that either one of the valve body and the valveseat of the main regulating valve comprises the elastic body, either oneof the valve body and the valve seat of the subsidiary regulating valvecomprises the elastic body, and each of the elastic body of the mainregulating valve and the elastic body of the subsidiary regulating valveis located in the state in which the elastic body is controlled suchthat the elastic body is prevented from deforming with respect to thedirections of the valve opening and closing movements. With themodification described above, in cases where the elastic body swells andundergoes a variation in volume, little variation in space between thevalve body and the valve seat occurs with the passage of time of use.Therefore, in cases where the pressure regulator is utilized forregulating the pressure of a gas having high dissolving characteristics,such as a dimethyl ether gas, a variation in gas flow rate due to theswelling of the elastic body does not occur, and the performance of thepressure regulator is capable of being obtained.

The second pressure regulator in accordance with the present inventioncomprises the main regulating valve, which performs the gas pressurereduction to the regulated pressure, the pressure loss occurring at themain regulating valve. The second pressure regulator in accordance withthe present invention also comprises the plunger, which interlocks themain regulating valve and the diaphragm with each other. The secondpressure regulator in accordance with the present invention furthercomprises the preliminary regulating valve, which is located on the sideupstream from the main regulating valve. The preliminary regulatingvalve operates by being interlocked with the main regulating valvethrough the plunger and reduces the unregulated pressure of thehigh-pressure gas coming from the gas introducing port, the pressureloss occurring at the preliminary regulating valve. Therefore, with thesecond pressure regulator in accordance with the present invention, incases where the gas having a high pressure flows through the gasintroducing port into the pressure regulator, the unregulated pressureis capable of being reduced by the preliminary regulating valve, and thepressure reduction and regulation to the regulated pressure is capableof being performed accurately by the main regulating valve. Accordingly,the follow-up characteristics with respect to fluctuation in unregulatedpressure are capable of being kept good. Also, as the unregulatedpressure becomes high, the pressure loss occurring at the preliminaryregulating valve becomes large. Therefore, the load with respect to themain regulating valve is capable of being kept light. In cases where theunregulated pressure is low, the pressure loss occurring at thepreliminary regulating valve is small, and therefore the second pressureregulator in accordance with the present invention is capable ofoperating in the same manner as that for the ordinary single-valve typepressure regulator.

With the second pressure regulator in accordance with the presentinvention, wherein the degree of the pressure loss occurring at thepreliminary regulating valve is capable of being adjusted, the load ofthe main regulating valve is capable of being altered, and the accuracywith which the pressure regulation is performed is capable of beingenhanced.

With the second pressure regulator in accordance with the presentinvention, wherein the valve body of the main regulating valve and thevalve body of the preliminary regulating valve are located on theplunger, the load for the pressure regulation acting upon the tworegulating valves is capable of being obtained with the same spring.Therefore, the response speed of the pressure regulator with respect tothe marked fluctuation in unregulated pressure is capable of being keptsufficiently higher than, for example, the cases wherein a single-valvetype pressure regulator for high pressures and a single-valve typepressure regulator for low pressures are connected in series andoperated. Also, with the second pressure regulator in accordance withthe present invention, wherein the valve body of the main regulatingvalve and the valve body of the preliminary regulating valve are locatedon the plunger, since only one set of the spring and the diaphragm isutilized, the structure of the pressure regulator is capable of beingkept as simple as the structure of one unit of a single-valve typepressure regulator.

The second pressure regulator in accordance with the present inventionmay be modified such that either one of the valve body and the valveseat of the main regulating valve comprises the elastic body, either oneof the valve body and the valve seat of the preliminary regulating valvecomprises the elastic body, and each of the elastic body of the mainregulating valve and the elastic body of the preliminary regulatingvalve is located in the state in which the elastic body is controlledsuch that the direction of the swelling deformation of the elastic bodybecomes different from the directions of the valve opening and closingoperations. With the modification described above, in cases where theelastic body swells and undergoes a variation in volume, littlevariation in space between the valve body and the valve seat occurs withthe passage of time of use. Therefore, in cases where the pressureregulator is utilized for regulating the pressure of a gas having highdissolving characteristics, such as a dimethyl ether gas, a variation ingas flow rate due to the swelling of the elastic body does not occur,and the performance of the pressure regulator is capable of beingobtained.

Also, as described above, each of the plunger, which links the mainregulating valve and the preliminary regulating valve with thediaphragm, and the supporter, which receives the pressure setting loadacting upon the diaphragm, should preferably be constituted of a lightmetal or a light metal alloy, such as aluminum or duralumin.Alternatively, each of the plunger and the supporter should preferablybe constituted of a polyamide, a polyacetal, a polybutyleneterephthalate, or a polypropylene, which is a crystalline resin. Asanother alternative, each of the plunger and the supporter shouldpreferably be constituted of an acetal, a polycarbonate, oracrylonitrile-butadiene-styrene, which is a non-crystalline resin, thenon-crystalline resin having a surface coated with an epoxy resin or apolyamide resin. In cases where each of the members described above isconstituted of one of the materials enumerated above, the membersoperating together with the diaphragm, to which the members describedabove are secured, are capable of being kept light in weight. Therefore,the response characteristics of the regulating valves with respect tothe displacement of the diaphragm are capable of being enhanced. Also,by virtue of low inertia force, a chattering phenomenon is capable ofbeing prevented from occurring. Further, the members are not affected bythe dissolving characteristics of the dimethyl ether gas, or the like,and do not undergo corrosion or cracking.

Also, as described above, the casing in which the diaphragm is locatedshould preferably be constituted of a polyamide, a polyacetal, apolybutylene terephthalate, or a polypropylene, which is a crystallineresin.

Alternatively, the casing in which the diaphragm is located shouldpreferably be constituted of an acetal, a polycarbonate, oracrylonitrile-butadiene-styrene, which is a non-crystalline resin, thenon-crystalline resin having a surface coated with an epoxy resin or apolyamide resin. In cases where the casing is constituted of one of thematerials enumerated above, by virtue of the utilization of the resin,the casing is capable of being kept light in weight and low in cost.Also, since the casing is capable of being formed with the ultrasonicbonding, the operation for assembling the casing is capable of beingperformed easily. Further, the casing is not affected by the dissolvingcharacteristics of the dimethyl ether gas, or the like, and do notundergo corrosion or cracking.

Particularly, in the cases of pressure regulators for stabilization offuel supply to solid oxide type fuel cells (SOFC's) and solid polymertype fuel cells (PEFC's), it is markedly undesirable that metal ions arepresent in the dimethyl ether gas supplied as the fuel. However, withthe second pressure regulator in accordance with the present invention,wherein the members described above are constituted of the resins, theproblems are capable of being prevented from occurring in that the metalions are dissolved out into the dimethyl ether gas supplied as the fuel.

With the third pressure regulator, which comprises the two governorsystems, the unregulated pressure of the high-pressure gas is capable ofbeing reduced in two stages to the regulated pressure. Therefore, withone pressure regulator, the regulated pressure having been reduced tothe set pressure is capable of being obtained accurately with respect toa wide unregulated pressure range, and the accuracy with which thepressure regulation is performed is capable of being enhanced. Also,since the two governor systems are located such that the directions ofdisplacement of the two diaphragms intersect with each other, the sizeof the pressure regulator is capable of being kept small.

The third pressure regulator in accordance with the present inventionmay be modified such that the first plunger and the second plunger arelocated such that the first plunger and the second plunger extend indirections which intersect at right angles with each other, a part ofthe second plunger is inserted for sliding movement into the gas flowpath extending from the first pressure regulating chamber to the secondpressure regulating chamber, and the second regulating valve is locatedwithin the first pressure regulating chamber. With the modificationdescribed above, the inside structure of the pressure regulator iscapable of being kept simple. Therefore, the modification describedabove is advantageous from the view point of production and cost.

With the third pressure regulator in accordance with the presentinvention, wherein the pressure receiving area of the first diaphragm ofthe first-stage governor system is smaller than the pressure receivingarea of the second diaphragm of the second-stage governor system, theregulation accuracy of the regulated pressure is capable of beingobtained reliably with the second diaphragm having the large pressurereceiving area, and the size of the entire pressure regulator is capableof being kept small by virtue of the reduction of the size of the firstdiaphragm.

The third pressure regulator in accordance with the present inventionmay be modified such that either one of the valve body and the valveseat of the first regulating valve comprises the elastic body, eitherone of the valve body and the valve seat of the second regulating valvecomprises the elastic body, and each of the elastic body of the firstregulating valve and the elastic body of the second regulating valve islocated in the state in which the elastic body is controlled such thatthe direction of the swelling deformation of the elastic body becomesdifferent from the directions of valve opening and closing operations.With the modification described above, in cases where the elastic bodyswells and undergoes a variation in volume, little variation in spacebetween the valve body and the valve seat occurs with the passage oftime of use. Therefore, in cases where the pressure regulator isutilized for regulating the pressure of a gas having high dissolvingcharacteristics, such as a dimethyl ether gas, a variation in gas flowrate due to the swelling of the elastic body does not occur, and theperformance of the pressure regulator is capable of being obtained. Inparticular, in cases where each of the elastic body of the firstregulating valve and the elastic body of the second regulating valve ismade from the urethane type rubber material, the elastic body is capableof being kept more resistant to the adverse effects of the gas havingthe high dissolving characteristics.

Also, as described above, each of the first plunger, which links thefirst regulating valve with the first diaphragm in the first-stagegovernor system, the second plunger, which links the second regulatingvalve with the second diaphragm in the second-stage governor system, thefirst supporter, which receives the pressure setting load acting uponthe first diaphragm, and the second supporter, which receives thepressure setting load acting upon the second diaphragm, shouldpreferably be constituted of a light metal or a light metal alloy, suchas aluminum or duralumin. Alternatively, each of the first plunger, thesecond plunger, the first supporter, and the second supporter shouldpreferably be constituted of a polyamide, a polyacetal, a polybutyleneterephthalate, or a polypropylene, which is a crystalline resin. Asanother alternative, each of the first plunger, the second plunger, thefirst supporter, and the second supporter should preferably beconstituted of an acetal, a polycarbonate, oracrylonitrile-butadiene-styrene, which is a non-crystalline resin, thenon-crystalline resin having a surface coated with an epoxy resin or apolyamide resin. In cases where each of the members described above isconstituted of one of the materials enumerated above, the membersoperating together with each of the diaphragms, to which the membersdescribed above are secured, are capable of being kept light in weight.Therefore, the response characteristics of the regulating valves withrespect to the displacement of the diaphragms are capable of beingenhanced. Also, by virtue of low inertia force, a chattering phenomenonis capable of being prevented from occurring. Further, the members arenot affected by the dissolving characteristics of the dimethyl ethergas, or the like, and do not undergo corrosion or cracking.

Also, as described above, the casing, in which the first-stage governorsystem and the second-stage governor system are located, shouldpreferably be constituted of a polyamide, a polyacetal, a polybutyleneterephthalate, or a polypropylene, which is a crystalline resin.Alternatively, the casing, in which the first-stage governor system andthe second-stage governor system are located, should preferably beconstituted of an acetal, a polycarbonate, oracrylonitrile-butadiene-styrene, which is a non-crystalline resin, thenon-crystalline resin having a surface coated with an epoxy resin or apolyamide resin. In cases where the casing is constituted of one of thematerials enumerated above, by virtue of the utilization of the resin,the casing is capable of being kept light in weight and low in cost.Also, since the casing is capable of being formed with the ultrasonicbonding, the operation for assembling the casing is capable of beingperformed easily. Further, the casing is not affected by the dissolvingcharacteristics of the dimethyl ether gas, or the like, and do notundergo corrosion or cracking.

Particularly, in the cases of pressure regulators for stabilization offuel supply to solid oxide type fuel cells (SOFC's) and solid polymertype fuel cells (PEFC's), it is markedly undesirable that metal ions arepresent in the dimethyl ether gas supplied as the fuel. However, withthe third pressure regulator in accordance with the present invention,wherein the members described above are constituted of the resins, theproblems are capable of being prevented from occurring in that the metalions are dissolved out into the dimethyl ether gas supplied as the fuel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing a first embodiment of the pressureregulator in accordance with the present invention,

FIG. 2 is a sectional view showing a modification of the firstembodiment of the pressure regulator in accordance with the presentinvention,

FIG. 3 is a graph showing the results of measurement of a variation inregulated pressure, which results were obtained with the pressureregulator shown in FIG. 1 in cases where an unregulated pressure of ahigh-pressure gas supplied to the pressure regulator shown in FIG. 1 wasaltered, and the results of measurement of a variation in regulatedpressure, which results were obtained with a pressure regulator of acomparative example in cases where the unregulated pressure of thehigh-pressure gas supplied to the pressure regulator of the comparativeexample was altered,

FIG. 4 is a graph showing the results of measurement of a variation ingas flow rate with respect to the passage of time, which results wereobtained with the pressure regulator shown in FIG. 1 in cases where adimethyl ether gas was utilized as the high-pressure gas supplied to thepressure regulator shown in FIG. 1, and the results of measurement of avariation in gas flow rate with respect to the passage of time, whichresults were obtained with the pressure regulator of the comparativeexample in cases where the dimethyl ether gas was utilized as thehigh-pressure gas supplied to the pressure regulator of the comparativeexample,

FIG. 5 is a sectional view showing a second embodiment of the pressureregulator in accordance with the present invention,

FIG. 6 is a graph showing the results of measurement of a variation inregulated pressure, which results were obtained with the pressureregulator shown in FIG. 5 in cases where an unregulated pressure of ahigh-pressure gas supplied to the pressure regulator shown in FIG. 5 wasaltered, and the results of measurement of a variation in regulatedpressure, which results were obtained with the pressure regulator of thecomparative example in cases where the unregulated pressure of thehigh-pressure gas supplied to the pressure regulator of the comparativeexample was altered,

FIG. 7 is a graph showing the results of measurement of a variation ingas flow rate with respect to the passage of time, which results wereobtained with the pressure regulator shown in FIG. 5 in cases where adimethyl ether gas was utilized as the high-pressure gas supplied to thepressure regulator shown in FIG. 5, and the results of measurement of avariation in gas flow rate with respect to the passage of time, whichresults were obtained with the pressure regulator of the comparativeexample in cases where the dimethyl ether gas was utilized as thehigh-pressure gas supplied to the pressure regulator of the comparativeexample,

FIG. 8 is a graph showing the results of measurement of a rise timeoccurring between when introduction of a high-pressure gas having anunregulated pressure into the pressure regulator shown in FIG. 5 wasbegun and when a regulated pressure obtained with the pressure regulatorshown in FIG. 5 became stable, which results were obtained in caseswhere the unregulated pressure was altered,

FIG. 9 is a graph showing the results of measurement of a rise timeoccurring between when introduction of the high-pressure gas having theunregulated pressure into a pressure regulator of a differentcomparative example was begun and when the regulated pressure obtainedwith the pressure regulator of the different comparative example becamestable, which results were obtained in cases where the unregulatedpressure was altered,

FIG. 10 is a sectional view showing a third embodiment of the pressureregulator in accordance with the present invention,

FIG. 11 is a graph showing the results of measurement of a variation inregulated pressure, which results were obtained with the pressureregulator shown in FIG. 10 in cases where an unregulated pressure of ahigh-pressure gas supplied to the pressure regulator shown in FIG. 10was altered,

FIG. 12 is a graph showing the results of measurement of a variation inoutlet flow rate, which results were obtained with the pressureregulator shown in FIG. 10 in cases where an unregulated pressure of ahigh-pressure gas supplied to the pressure regulator shown in FIG. 10was altered,

FIG. 13 is a graph showing the results of measurement of a variation inregulated pressure, which results were obtained with the pressureregulator shown in FIG. 10 in cases where an outlet flow rate in thepressure regulator shown in FIG. 10 was altered,

FIG. 14 is a sectional view showing the pressure regulator of thecomparative example,

FIG. 15A is a schematic view showing a fundamental structure of anordinary single-valve type pressure regulator,

FIG. 15B is a schematic view showing a fundamental structure of anordinary duplex-valve type pressure regulator, and

FIG. 15C is a schematic view showing a fundamental structure of anordinary modified duplex-valve type pressure regulator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will hereinbelow be described in further detailwith reference to the accompanying drawings.

FIG. 1 is a sectional view showing a first embodiment of the pressureregulator in accordance with the present invention.

With reference to FIG. 1, a pressure regulator 100, which is the firstembodiment of the pressure regulator in accordance with the presentinvention, comprises a diaphragm 120, which partitions off a regionwithin a casing 110 into a pressure regulating chamber 111 and anatmospheric chamber 112. The pressure regulator 100 also comprises a gasintroducing port 113, through which a high-pressure gas having anunregulated pressure is introduced into the pressure regulator 100. Thepressure regulator 100 further comprises a main regulating valve 130,which operates by being interlocked with the diaphragm 120. The mainregulating valve 130 performs operations for opening and closing anaperture 133, through which the gas introducing port 113 and thepressure regulating chamber 111 communicate with each other. Theoperations of the main regulating valve 130 for opening and closing theaperture 133 are performed from the unregulated pressure side. The mainregulating valve 130 thus reduces the unregulated pressure of thehigh-pressure gas to a regulated pressure. The pressure regulator 100still further comprises a subsidiary regulating valve 140, whichoperates by being interlocked with the diaphragm 120. The subsidiaryregulating valve 140 performs operations for opening and closing anaperture 143, through which the gas introducing port 113 and thepressure regulating chamber 111 communicate with each other. Theoperations of the subsidiary regulating valve 140 for opening andclosing the aperture 143 are performed from the regulated pressure side.The pressure regulator 100 also comprises a gas discharging port 114,through which the gas having been pressure-regulated through thepressure regulating chamber 111 and having the regulated pressure isdischarged from the pressure regulator 100. The pressure regulator 100further comprises a pressure setting section 150 for adjusting aquantity of displacement of the diaphragm 120, which receives theregulated pressure within the pressure regulating chamber 111 and isthereby displaced. The diaphragm 120, the main regulating valve 130, andthe subsidiary regulating valve 140 are linked and interlocked with oneanother by a plunger 160. The pressure regulator 100 still furthercomprises a duplex-valve adjustor 170, which acts as the adjustmentmeans for adjusting the position of a valve seat of the subsidiaryregulating valve 140 and thereby adjusting a value of a pressure loss,which occurs at the subsidiary regulating valve 140.

Each of the main regulating valve 130 and the subsidiary regulatingvalve 140 reduces the unregulated pressure of the high-pressure gas tothe regulated pressure, a pressure loss occurring at each of the mainregulating valve 130 and the subsidiary regulating valve 140. The mainregulating valve 130 and the subsidiary regulating valve 140 are locatedsuch that the force, which acts upon the main regulating valve 130 dueto the pressure loss occurring at the main regulating valve 130, and theforce, which acts upon the subsidiary regulating valve 140 due to thepressure loss occurring at the subsidiary regulating valve 140, canceleach other. With the duplex-valve adjustor (adjustment means) 170, thevalue of the pressure loss, which the subsidiary regulating valve 140receives, is capable of being adjusted such that the value of thepressure loss becomes equal to the value of the pressure loss, which themain regulating valve 130 receives.

Also, each of a valve body 131 of the main regulating valve 130 and avalve body 141 of the subsidiary regulating valve 140 is constituted ofan elastic body, which is formed as an O-ring. Each of the elastic bodyof the main regulating valve 130 and the elastic body of the subsidiaryregulating valve 140 is located in a state in which the elastic body iscontrolled by a peripheral groove section 163 such that the elastic bodyis prevented from deforming with respect to directions of valve openingand closing movements. Therefore, a dimethyl ether gas, or the like,which will have adverse effects, such as swelling effects, upon theelastic body, is capable of being used as the high-pressure gas.

The structure of the pressure regulator 100 will hereinbelow bedescribed in more detail.

The casing 110 comprises a casing main body section 115 and a coversection 116. The casing main body section 115 and the cover section 116are joined to each other with the diaphragm 120 interveningtherebetween. In this manner, the space within the casing 110 ispartitioned off by the diaphragm 120 into the pressure regulatingchamber 111, which is located on the side of the casing main bodysection 115, and the atmospheric chamber 112, which is located on theside of the cover section 116. The pressure regulating chamber 111 has acertain volume and is capable of relaxing pressure vibration of the gas,which has passed through the main regulating valve 130.

The diaphragm 120 receives the regulated pressure within the pressureregulating chamber 111 and is thus capable of undergoing elasticdisplacement in accordance with the difference in pressure between thepressure regulating chamber 111 and the atmospheric chamber 112. On theside of the casing main body section 115, the plunger 160 is secured toa center region of the diaphragm 120. Also, on the side of the coversection 116, a supporter 180 is secured to the center region of thediaphragm 120. The plunger 160 and the supporter 180 are capable ofmoving together in the axial direction of the plunger 160 and thesupporter 180 in accordance with the displacement of the diaphragm 120.

The plunger 160 comprises a trunk section 161, which is secured to thediaphragm 120 and located within the pressure regulating chamber 111,and a shaft section 162, which extends in the axial direction of theplunger 160 from an end of the trunk section 161. The shaft section 162is provided with two peripheral groove sections 163, 163, which arelocated at a predetermined spacing from each other. The valve body 131of the main regulating valve 130, which valve body is constituted of theO-ring (i.e., the elastic body), is fitted into one of the peripheralgroove sections 163, 163. Also, the valve body 141 of the subsidiaryregulating valve 140, which valve body is constituted of the O-ring(i.e., the elastic body), is fitted into the other peripheral groovesection 163. A secondary gas flow path 164 is formed through the centerareas of the trunk section 161 and the shaft section 162 of the plunger160, such that the secondary gas flow path 164 extends from one end ofthe plunger 160 to the other end of the plunger 160. A side wall of thetrunk section 161 has a communication aperture 165, through which thepressure regulating chamber 111 and the secondary gas flow path 164communicate with each other.

The supporter 180 is provided with a bolt section 182, which continuesfrom a center area of a flange section 181 located in close contact withthe diaphragm 120. The bolt section 182 of the supporter 180 passesthrough the center area of the diaphragm 120 and is engaged with athreaded end section of the secondary gas flow path 164 of the plunger160, which is located on the side opposite to the flange section 181 ofthe supporter 180. The supporter 180 is thus linked to the plunger 160.

One end section of a pressure regulating spring 151 of the pressuresetting section 150, which is located within a tubular section 116 a ofthe cover section 116, is brought into abutment with the flange section181 of the supporter 180. The other end section of the pressureregulating spring 151 is brought into abutment with a pressureregulating screw (adjustor) 152, which is engaged by threads with aninside wall of the tubular section 116 a such that the position of thepressure regulating screw 152 is capable of being adjusted. The urgingforce of the pressure regulating spring 151 acting upon the diaphragm120 is adjusted in accordance with the adjustment of the position of thepressure regulating screw 152 with respect to the axial direction of thetubular section 116 a. A center area of the pressure regulating screw152 has a communication through-hole 153, which passes through thecenter area of the pressure regulating screw 152 in the axial directionof the pressure regulating screw 152. Through the communicationthrough-hole 153 of the pressure regulating screw 152, the atmosphericchamber 112 is open to the ambient atmosphere.

A side wall of the casing main body section 115 is provided with the gasintroducing port 113, through which the high-pressure gas is introducedinto the pressure regulator 100. A first connector 118 for introducingthe high-pressure gas, such as the dimethyl ether gas, which has theunregulated pressure and is supplied from a gas cylinder, or the like,is connected to the gas introducing port 113. The gas introducing port113 continues into an introduced gas hole 121, which passes through thewall of the casing main body section 115 toward the center area of thecasing main body section 115 and communicates with a primary gas flowpath 122 formed in the inside of the casing main body section 115. Also,the casing main body section 115 is provided with a partition wall 115a, which partitions off the primary gas flow path 122 and the pressureregulating chamber 111 from each other. The aperture 133, which isopened and closed by the main regulating valve 130, is formed at thecenter area, which is defined by the partition wall 115 a. The shaftsection 162 of the plunger 160 is inserted for sliding movement into theaperture 133. An area of a side surface of the partition wall 115 a,which area stands facing the primary gas flow path 122 and is located inthe vicinity of the aperture 133, acts as a valve seat 132 of the mainregulating valve 130.

In accordance with the movement of the plunger 160, the valve body 131of the main regulating valve 130 comes into close contact with the valveseat 132 and closes the aperture 133. In cases where the valve body 131of the main regulating valve 130 moves away from the valve seat 132 andopens the aperture 133 in accordance with the movement of the plunger160, a quantity of the gas in accordance with the quantity of theopening of the aperture 133 passes through the space between the insideperipheral surface of the partition wall 115 a defining the aperture 133and the outside peripheral surface of the plunger 160 and flows from theprimary gas flow path 122 into the pressure regulating chamber 111.

The duplex-valve adjustor 170 having a tubular shape is fitted from anend of the casing main body section 115, which end is located on theside of the gas discharging port 114, into the primary gas flow path122. The duplex-valve adjustor 170 has a hole on a tail end side, whichhole acts as the gas discharging port 114 for discharging the gas havingthe regulated pressure. The gas discharging port 114 is connected to asecond connector 119 for receiving the gas having the regulatedpressure. The duplex-valve adjustor 170 has outside peripheral threads,which are engaged with end threads of the casing main body section 115,and the position of the duplex-valve adjustor 170 is thus adjusted. Theduplex-valve adjustor 170 is secured at the adjusted position by a locknut 117.

The duplex-valve adjustor 170 also has a leading end tube section 171,which is inserted for sliding movement into the primary gas flow path122. A sealing material 172 is fitted onto the outer periphery of theleading end tube section 171. The sealing material 172 is brought intoclose contact with a region of an inside peripheral surface of theprimary gas flow path 122, which region is located on the side moreoutward than the introduced gas hole 121. In this manner, the sealingmaterial 172 performs sliding movement sealing at the outside peripheryof the leading end tube section 171. Further, a part of the shaftsection 162 of the plunger 160, which part is located between the valvebody 131 of the main regulating valve 130 and the valve body 141 of thesubsidiary regulating valve 140, is inserted for sliding movement intothe aperture 143 of the leading end tube section 171. An area of a sidesurface of the leading end tube section 171, which area stands facingthe gas discharging port 114 and is located in the vicinity of theaperture 143, acts as a valve seat 142 of the subsidiary regulatingvalve 140.

In accordance with the movement of the plunger 160, the valve body 141of the subsidiary regulating valve 140 comes into close contact with thevalve seat 142 and closes the aperture 143 of the leading end tubesection 171. In cases where the valve body 141 of the subsidiaryregulating valve 140 moves away from the valve seat 142 and opens theaperture 143 in accordance with the movement of the plunger 160, aquantity of the gas in accordance with the quantity of the opening ofthe aperture 143 passes through the space between the inside peripheralsurface of the aperture 143 and the outside peripheral surface of theplunger 160 and flows from the primary gas flow path 122 into the gasdischarging port 114, which is located on the regulated pressure side.

The position in the casing main body section 115, to which theduplex-valve adjustor 170 acting as the adjustment means is inserted, isadjusted such that, at the time at which the valve body 131 of the mainregulating valve 130 comes into close contact with the valve seat 132 ofthe main regulating valve 130 and closes the aperture 133, the valvebody 141 of the subsidiary regulating valve 140 also comes into closecontact with the valve seat 142 of the subsidiary regulating valve 140and closes the aperture 143, and such that the value of the pressureloss occurring at the main regulating valve 130 and the value of thepressure loss occurring at the subsidiary regulating valve 140 are equalto each other.

In accordance with the movement of the diaphragm 120, the mainregulating valve 130 and the subsidiary regulating valve 140 co-operatewith each other in order to reduce and regulate the unregulated pressureinto the predetermined regulated pressure regardless of the fluctuationin unregulated pressure. How the main regulating valve 130 and thesubsidiary regulating valve 140 operate will be described hereinbelow.

Firstly, the gas having flowed from the gas introducing port 113 intothe primary gas flow path 122 passes through the main regulating valve130, and the unregulated pressure of the gas is reduced into theregulated pressure. The gas having the regulated pressure passes throughthe secondary gas flow path 164 within the plunger 160 into the gasdischarging port 114. The force, which is of a level equal to theproduct of the value of the pressure loss occurring at this time at themain regulating valve 130 and the projected valve body area of the mainregulating valve 130, arises in the direction, which closes the mainregulating valve 130 and retreats the plunger 160 (i.e., in the leftwarddirection in FIG. 1).

Also, the gas having the unregulated pressure within the primary gasflow path 122 passes through the aperture 143, i.e. through the spacebetween the inside peripheral surface of the leading end tube section171 of the duplex-valve adjustor 170 and the outside peripheral surfaceof the plunger 160, to the subsidiary regulating valve 140. The gas thenpasses through the subsidiary regulating valve 140, and the unregulatedpressure of the gas is reduced to the regulated pressure. The gas havingthe regulated pressure flows to the gas discharging port 114. The gasdischarging port 114 communicates with the pressure regulating chamber111 through the secondary gas flow path 164. At this time, the force,which is of a level equal to the product of the value of the pressureloss occurring at the subsidiary regulating valve 140 and the projectedvalve body area of the subsidiary regulating valve 140, arises in thedirection, which opens the subsidiary regulating valve 140 and advancesthe plunger 160 (i.e., in the rightward direction in FIG. 1).Specifically, the force acting upon the main regulating valve 130 andthe force acting upon the subsidiary regulating valve 140 arise in thereverse directions.

Ordinarily, the value of the pressure loss, which occurs in the flowpath of the main regulating valve 130, and the value of the pressureloss, which occurs in the flow path of the subsidiary regulating valve140, will be different from each other. However, in this embodiment,since the duplex-valve adjustor 170 is located such that theduplex-valve adjustor 170 is capable of being moved for positionadjustment in the axial direction, the value of the pressure loss, whichoccurs at the subsidiary regulating valve 140, is capable of beingaltered. Therefore, the value of the pressure loss, which occurs at themain regulating valve 130, is capable of being accurately canceled bythe value of the pressure loss, which occurs in at the subsidiaryregulating valve 140.

Further, the diaphragm 120 is supported by the plunger 160 and thesupporter 180. The diaphragm 120 is kept at the position, at which theforce due to the pressure difference between the regulated pressure andthe atmospheric pressure and the urging force of the pressure regulatingspring 151 are balanced with each other. In cases where the regulatedpressure varies in accordance with a variation in quantity of the gasdischarged from the gas discharging port 114, the variation inunregulated pressure, and the like, the quantity of the displacement ofthe diaphragm 120 varies in accordance with the variation in regulatedpressure, and the position of the plunger 160 varies. Also, the mainregulating valve 130 and the subsidiary regulating valve 140 move inaccordance with the variation in position of the plunger 160 and keepthe regulated pressure at the predetermined pressure. The urging forceof the pressure regulating spring 151 is capable of being varied by theadjustment of the position of the pressure regulating screw 152 of thepressure setting section 150, and the regulated pressure is thus capableof being set at an arbitrary pressure.

Furthermore, each of the valve body 131 of the main regulating valve 130and the valve body 141 of the subsidiary regulating valve 140 isconstituted of the elastic body, which is formed as the O-ring.Therefore, in cases where the gas having the high dissolvingcharacteristics, such as the dimethyl ether gas, is introduced into thepressure regulator 100, and each of the O-rings is brought into contactwith the gas having the high dissolving characteristics and undergoesswelling and expansion in volume, the variation in volume of each of theO-rings is restricted so as to occur only in the direction, which isnormal to the directions of valve opening and closing movements.Accordingly, the variation in pressure loss and the variation in gasflow rate due to the expansion in volume of each of the O-rings arecapable of being suppressed.

Also, the pressure reduction from the unregulated pressure to theregulated pressure is performed by the combination of the two regulatingvalves, i.e. the combination of the main regulating valve 130 and thesubsidiary regulating valve 140. Therefore, the value of the pressureloss occurring at each of the two regulating valves is capable of beingkept to be one half of the value of the pressure loss, which occurs incases where the pressure reduction is performed with only one regulatingvalve. Accordingly, the space between the valve body and the valve seatof each of the two regulating valves is capable of being set to becomparatively large. As a result, reliable performance is capable ofbeing obtained in cases where the unregulated pressure is markedly high.Specifically, the reliable performance is capable of being obtained incases where the degree of the required pressure reduction is high, thevalve space between the valve body and the valve seat is set to bemarkedly small, and therefore a slight variation in valve space affectsthe regulated pressure.

In the first embodiment described above, each of the valve body 131 ofthe main regulating valve 130 and the valve body 141 of the subsidiaryregulating valve 140 is constituted of the elastic body, which is formedas the O-ring. Alternatively, each of the valve seat 132 of the mainregulating valve 130 and the valve seat 142 of the subsidiary regulatingvalve 140 may be constituted of the elastic body, which is formed as theO-ring. In such cases, each of the elastic body acting as the valve seat132 and the elastic body acting as the valve seat 142 is located in astate in which the elastic body is controlled by a peripheral groovestructure, or the like, such that the elastic body is prevented fromdeforming with respect to the directions of valve opening and closingmovements. As another alternative, an elastic body other than the O-ringmay be employed.

FIG. 2 is a sectional view showing a modification of the firstembodiment of the pressure regulator in accordance with the presentinvention. A pressure regulator 200, which is the modification of thefirst embodiment of the pressure regulator in accordance with thepresent invention, has a structure basically identical with thestructure of the pressure regulator 100 shown in FIG. 1, except that thepressure regulator 200 further comprises a valve closing spring 290,which is located within a pressure regulating chamber 211. In FIG. 2,similar elements are numbered with the similar reference numerals withrespect to FIG. 1.

The valve closing spring 290 urges a plunger 260 toward the directionthat retreats the plunger 260 (the leftward direction in FIG. 2), i.e.toward the direction of closing of a main regulating valve 230.Specifically, the valve closing spring 290 is constituted of a coiledspring. The valve closing spring 290 is located in the vicinity of theoutside periphery of a trunk section 261 and in a contracted state suchthat one end of the valve closing spring 290 is in abutment with a sidesurface of a partition wall 215 a of a casing main body section 215, andsuch that the other end of the valve closing spring 290 is in abutmentwith a side surface of the plunger 260 so as to push a diaphragm 220toward the side of the atmospheric chamber 212.

Also, the pressure adjustment with a pressure regulating screw 252 of apressure setting section 250 is set such that the urging force of apressure regulating spring 251 is larger by the urging force of thevalve closing spring 290 than the urging force of the pressureregulating spring 151 in the embodiment of FIG. 1.

With the modification of the first embodiment of the pressure regulatorin accordance with the present invention, which modification is providedwith the valve closing spring 290 described above, in cases where theurging force of the pressure regulating spring 251 is set to be small,and the set pressure of the regulated pressure is low, the diaphragm 220is capable of being displaced in accordance with the pressure differencebetween the pressure regulating chamber 211 and an atmospheric chamber212, and accurate operations of the main regulating valve 230 and asubsidiary regulating valve 240 are capable of being obtained inaccordance with the movement of the plunger 260. Therefore, reliablepressure regulation is capable of being performed. Also, in cases wherethe urging force of the pressure regulating spring 251 is set to besmaller than the urging force of the valve closing spring 290, theplunger 260 is capable of being retreated by the urging force of thevalve closing spring 290, and a blocking state, in which the mainregulating valve 230 and the subsidiary regulating valve 240 are closed,is capable of being obtained. In this manner, the gas discharging from agas discharging port 214 is capable of being ceased.

The first embodiment of FIG. 1 described above, which is not providedwith the valve closing spring 290 described above, is based upon thepresumption that the regulated pressure is ordinarily set at acomparatively high pressure. With the first embodiment of FIG. 1described above, in cases where the set pressure of the regulatedpressure is sufficiently higher than the atmospheric pressure, acomparatively large force in accordance with the pressure differencebetween the regulated pressure and the atmospheric pressure acts uponthe diaphragm 120, and the accurate operations for pressure regulationare capable of being obtained with the main regulating valve 130 and thesubsidiary regulating valve 140 moving together with the plunger 160.However, with the first embodiment of FIG. 1 described above, in caseswhere the regulated pressure is set at a low pressure close to theatmospheric pressure, the force for displacing the diaphragm 120 inaccordance with the pressure difference between the regulated pressureand the atmospheric pressure becomes small. Also, a force capable ofdisplacing the diaphragm 120 in the direction of retreat of the plunger160 does not occur besides the force due to the pressure differencebetween the regulated pressure and the atmospheric pressure. Therefore,the response characteristics become comparatively bad, and the pressureregulating effects become unstable. However, with the aforesaidmodification of the first embodiment of the pressure regulator inaccordance with the present invention, the force for displacing thediaphragm 220 in the direction of retreat of the plunger 260 is obtainedwith the provision of the valve closing spring 290. Therefore, with theaforesaid modification, in cases where the regulated pressure is set tobe low, the response characteristics of the diaphragm 220 are capable ofbeing enhanced, and the reliable pressure regulating effects are capableof being obtained.

The results of experiments conducted for evaluating the pressureregulating effects of the first embodiment of the pressure regulator inaccordance with the present invention (i.e., the pressure regulator 100having the structure illustrated in FIG. 1) and the results ofexperiments conducted for evaluating the pressure regulating effects ofa pressure regulator of a comparative example (i.e., a single-valve typepressure regulator 500 illustrated in FIG. 14) will be describedhereinbelow with reference to FIG. 3 and FIG. 4. FIG. 3 is a graphshowing the results of measurement of a variation in regulated pressure,which results were obtained with the pressure regulator 100 shown inFIG. 1 in cases where an unregulated pressure of a high-pressure gassupplied to the pressure regulator 100 shown in FIG. 1 was altered, andthe results of measurement of a variation in regulated pressure, whichresults were obtained with the single-valve type pressure regulator 500of the comparative example in cases where the unregulated pressure ofthe high-pressure gas supplied to the single-valve type pressureregulator 500 of the comparative example was altered. FIG. 4 is a graphshowing the results of measurement of a variation in gas flow rate withrespect to the passage of time, which results were obtained with thepressure regulator 100 shown in FIG. 1 in cases where a dimethyl ethergas was utilized as the high-pressure gas supplied to the pressureregulator 100 shown in FIG. 1, and the results of measurement of avariation in gas flow rate with respect to the passage of time, whichresults were obtained with the single-valve type pressure regulator 500of the comparative example in cases where the dimethyl ether gas wasutilized as the high-pressure gas supplied to the single-valve typepressure regulator 500 of the comparative example.

The single-valve type pressure regulator 500 illustrated in FIG. 14 hasa fundamental structure basically identical with the structure shown inFIG. 15A. In FIG. 14, similar elements are numbered with the samereference numerals with respect to FIG. 15A. With the single-valve typepressure regulator 500 illustrated in FIG. 14, the high-pressure gashaving the unregulated pressure is introduced through the gasintroducing port 505 and passes through the regulating valve 506, whichperforms the valve opening and closing operations in accordance with thedisplacement of the diaphragm 504. (A valve body 506 a of the regulatingvalve 506 is constituted of a rigid body, and a valve seat 506 b of theregulating valve 506 is constituted of an elastic body.) The gas thenflows into the pressure regulating chamber 502, which is partitioned offby the diaphragm 504 from the atmospheric chamber 503. The gas havingthe regulated pressure within the pressure regulating chamber 502 isdischarged through the gas discharging port 508. The urging force actingupon the diaphragm 504 is adjusted by a pressure setting section 509,which is provided with a pressure regulating spring 509 a and a pressureregulating screw 509 b. The regulated pressure is thus set.

MEASUREMENT EXAMPLE 1

In Measurement Example 1, measurement was made to find a variation inregulated pressure in cases where an unregulated pressure of ahigh-pressure gas (an inert gas) supplied to each of the pressureregulators was altered. The results of the measurement obtained with thepressure regulator 100 of FIG. 1 in the example in accordance with thepresent invention are indicated by the solid line in FIG. 3. Also, theresults of the measurement obtained with the single-valve type pressureregulator 500 of FIG. 14 in the comparative example are indicated by thebroken line in FIG. 3.

In both the example in accordance with the present invention and thecomparative example, the regulated pressure was set by the adjustment ofthe pressure regulating screw 152 of the pressure setting section 150 orthe pressure regulating screw 509 b of the pressure setting section 509,such that, when the unregulated pressure was equal to 400 kPa, theregulated pressure became equal to 50 kPa. At this time, the gas flowrate was equal to 40 mL/min.

As indicated by the solid line in the graph of FIG. 3, with the pressureregulator 100 of FIG. 1 in accordance with the present invention, incases where the unregulated pressure was altered over the range of 50kPa to 2000 kPa, the regulated pressure did not vary and was set at theset value (50 kPa), and the predetermined regulated pressure was kept.It was capable of being confirmed that, with the functions of the mainregulating valve 130 and the subsidiary regulating valve 140 of thepressure regulator 100 of FIG. 1 in accordance with the presentinvention, the adverse effect of the force, which accompanies thepressure loss, was capable of being canceled, and the pressureregulating effects were capable of being obtained with respect to thewide unregulated pressure range.

However, as indicated by the broken line in the graph of FIG. 3, withthe single-valve type pressure regulator 500 of FIG. 14 in thecomparative example, in cases where the unregulated pressure fell withinthe region lower than 400 kPa, the regulated pressure was higher thanthe set value (50 kPa). Also, in cases where the unregulated pressurefell within the region higher than 400 kPa, the regulated pressurevaried such that the regulated pressure became lower than the set value(50 kPa), and such that, as the unregulated pressure became high, theregulated pressure became low as a whole. In this manner, with thesingle-valve type pressure regulator 500 of FIG. 14 in the comparativeexample, the regulated pressure was not capable of being kept at thepredetermined pressure.

MEASUREMENT EXAMPLE 2

In Measurement Example 2, measurement was made to find a variation ingas flow rate with respect to the passage of time in cases where adimethyl ether gas, which was a typical gas causing an elastic material(a rubber material) to swell, was utilized as the high-pressure gassupplied to each of the pressure regulators. The results of themeasurement obtained with the pressure regulator 100 of FIG. 1 in theexample in accordance with the present invention are indicated by thesolid line in FIG. 4. Also, the results of the measurement obtained withthe single-valve type pressure regulator 500 of FIG. 14 in thecomparative example are indicated by the broken line in FIG. 4. Theinitial flow rate of the dimethyl ether gas was equal to 80 mL/min. Thetest was conducted at a temperature, at which the vapor pressure wasequal to 400 kPa.

As indicated by the solid line in the graph of FIG. 4, with the pressureregulator 100 of FIG. 1 in accordance with the present invention, incases where a period of time of as long as 120 minutes had elapsed, theflow rate of the discharged gas did not vary and was kept at the initialflow rate. It was capable of being confirmed that, with the pressureregulator 100 of FIG. 1 in accordance with the present invention, eventhough the O-rings were subjected to the swelling due to the contactwith the gas, adverse effects upon the gas flow rate did not occur.

However, as indicated by the broken line in the graph of FIG. 4, withthe single-valve type pressure regulator 500 of FIG. 14 in thecomparative example, due to a variation in valve space accompanying theswelling of the valve seat 506 b constituted of the elastic body, thegas flow rate begun becoming low at the time at which a period of timeof approximately 15 minutes had elapsed after the start of themeasurement. Thereafter, the gas flow rate became markedly low with thepassage of time. At the time at which a period of time of approximately60 minutes had elapsed after the start of the measurement, the gas flowrate became 0 (zero), and the gas could not be discharged any more.

A second embodiment of the pressure regulator in accordance with thepresent invention will be described hereinbelow. FIG. 5 is a sectionalview showing a second embodiment of the pressure regulator in accordancewith the present invention.

With reference to FIG. 5, a pressure regulator 300, which is the secondembodiment of the pressure regulator in accordance with the presentinvention, is used for the stabilization of fuel supply to solid oxidetype fuel cells (SOFC's) and solid polymer type fuel cells (PEFC's).Also, a dimethyl ether gas is utilized as the high-pressure gas to besupplied to the pressure regulator 300. The pressure regulator 300comprises a diaphragm 320, which partitions off a region within a casing310 into a pressure regulating chamber 311 and an atmospheric chamber312. The pressure regulator 300 also comprises a gas introducing port313, through which the high-pressure gas having an unregulated pressureis introduced into the pressure regulator 300. The pressure regulator300 further comprises a main regulating valve 330, which operates bybeing interlocked with the diaphragm 320. The main regulating valve 330performs operations for opening and closing an aperture 333, throughwhich a preliminary chamber 322 and the pressure regulating chamber 311communicate with each other. The operations of the main regulating valve330 for opening and closing the aperture 333 are performed from the sideopposite to the pressure regulating chamber 311. The main regulatingvalve 330 thus reduces the gas pressure within the preliminary chamber322 to a regulated pressure. The pressure regulator 300 still furthercomprises a preliminary regulating valve 340, which operates by beinginterlocked with the diaphragm 320. The preliminary regulating valve 340performs operations for opening and closing an aperture 343, throughwhich the gas introducing port 313 and the preliminary chamber 322communicate with each other. The operations of the preliminaryregulating valve 340 for opening and closing the aperture 343 areperformed from the unregulated pressure side. The pressure regulator 300also comprises a gas discharging port 314, through which the gas havingbeen pressure-regulated through the pressure regulating chamber 311 andhaving the regulated pressure is discharged from the pressure regulator300. The pressure regulator 300 further comprises a pressure settingsection 350 for adjusting a quantity of displacement of the diaphragm320, which receives the regulated pressure within the pressureregulating chamber 311 and is thereby displaced. The diaphragm 320, themain regulating valve 330, and the preliminary regulating valve 340 arelinked and interlocked with one another by a plunger 360. The pressureregulator 300 still further comprises an adjustor 370, which acts as theadjustment means for adjusting the position of a valve seat of thepreliminary regulating valve 340 and thereby adjusting a value of apressure loss, which occurs at the preliminary regulating valve 340.

The main regulating valve 330 and the preliminary regulating valve 340co-operate to perform the pressure reduction of the unregulated pressureof the high-pressure gas to the regulated pressure, a pressure lossoccurring at each of the main regulating valve 330 and the preliminaryregulating valve 340. With the adjustor (adjustment means) 370, theratio of the value of the pressure loss, which occurs at the preliminaryregulating valve 340, to the value of the pressure loss, which occurs atthe main regulating valve 330, is capable of being adjusted.

Also, each of a valve body 331 of the main regulating valve 330 and avalve body 341 of the preliminary regulating valve 340 is constituted ofan elastic body, which is formed as an O-ring. Each of the elastic bodyof the main regulating valve 330 and the elastic body of the preliminaryregulating valve 340 is located in a state in which the elastic body iscontrolled by a peripheral groove section 363 such that the elastic bodyis prevented from deforming with respect to directions of valve openingand closing movements. Therefore, a dimethyl ether gas, or the like,which will have adverse effects, such as swelling effects, upon theelastic body, is capable of being used as the high-pressure gas.

The structure of the casing 310, the structure of the diaphragm 320, andthe structure of the supporter 380 are basically identical with thestructure of the casing 110, the structure of the diaphragm 120, and thestructure of the supporter 180, respectively, in the first embodimentdescribed above.

The plunger 360 comprises a trunk section 361, which is secured to thediaphragm 320 and located within the pressure regulating chamber 311,and a shaft section 362, which extends in the axial direction of theplunger 360 from an end of the trunk section 361. The shaft section 362is provided with two peripheral groove sections 363, 363, which arelocated at a predetermined spacing from each other. The valve body 331of the main regulating valve 330, which valve body is constituted of theO-ring (i.e., the elastic body), is fitted into one of the peripheralgroove sections 363, 363. Also, the valve body 341 of the preliminaryregulating valve 340, which valve body is constituted of the O-ring(i.e., the elastic body), is fitted into the other peripheral groovesection 363.

The casing main body section 315 is provided with a partition wall 315a, which partitions off the preliminary chamber 322 and the pressureregulating chamber 311 from each other. The aperture 333, which isopened and closed by the main regulating valve 330, is formed at thecenter area, which is defined by the partition wall 315 a. The shaftsection 362 of the plunger 360 is inserted for sliding movement into theaperture 333. An area of a side surface of the partition wall 315 a,which area stands facing the preliminary chamber 322 and is located inthe vicinity of the aperture 333, acts as a valve seat 332 of the mainregulating valve 330.

In accordance with the movement of the plunger 360, the valve body 331of the main regulating valve 330 comes into close contact with the valveseat 332 and closes the aperture 333. In cases where the valve body 331of the main regulating valve 330 moves away from the valve seat 332 andopens the aperture 333 in accordance with the movement of the plunger360, a quantity of the gas in accordance with the quantity of theopening of the aperture 333 passes through the space between the insideperipheral surface of the partition wall 315 a defining the aperture 333and the outside peripheral surface of the plunger 360 and flows from thepreliminary chamber 322 into the pressure regulating chamber 311.

The adjustor 370 having a tubular shape is fitted from an end of thecasing main body section 315, which end is located on the side of thegas introducing port 313, into the preliminary chamber 322. The adjustor370 has outside peripheral threads, which are engaged with end threadsof the casing main body section 315, and the position of the adjustor370 is thus adjusted. The adjustor 370 is secured at the adjustedposition by a lock nut 317. The adjustor 370 has a hole on a tail endside, which hole acts as the gas introducing port 313 for introducingthe high-pressure gas into the pressure regulator 300. A first connector318 for introducing the high-pressure gas, such as the dimethyl ethergas, which has the unregulated pressure and is supplied from a gascylinder, or the like, is connected to the gas introducing port 313.

A side section of the pressure regulating chamber 311 is provided withthe gas discharging port 314, which communicates with the pressureregulating chamber 311 and is open to the exterior. The gas having theregulated pressure obtained through the pressure regulation isdischarged through the gas discharging port 314. The gas dischargingport 314 is connected to a second connector (not shown) for receivingthe gas having the regulated pressure.

The adjustor 370 also has a leading end tube section 371, which isinserted for sliding movement into the preliminary chamber 322. Asealing material 372 is fitted onto the outer periphery of the leadingend tube section 371. The sealing material 372 is brought into closecontact with an inside peripheral surface of the preliminary chamber322. In this manner, the sealing material 372 performs sliding movementsealing at the outside periphery of the leading end tube section 371.

Further, a part of the shaft section 362 of the plunger 360, which partis located between the valve body 331 of the main regulating valve 330and the valve body 341 of the preliminary regulating valve 340, isinserted for sliding movement into the aperture 343 of the leading endtube section 371. An area of a side surface of the leading end tubesection 371, which area stands facing the gas introducing port 313 andis located in the vicinity of the aperture 343, acts as a valve seat 342of the preliminary regulating valve 340.

In accordance with the movement of the plunger 360, the valve body 341of the preliminary regulating valve 340 comes into close contact withthe valve seat 342 and closes the aperture 343 of the leading end tubesection 371. In cases where the valve body 341 of the preliminaryregulating valve 340 moves away from the valve seat 342 and opens theaperture 343 in accordance with the movement of the plunger 360, aquantity of the gas in accordance with the quantity of the opening ofthe aperture 343 passes through the space between the inside peripheralsurface of the aperture 343 and the outside peripheral surface of theplunger 360 and flows from the gas introducing port 313 into thepreliminary chamber 322.

The position in the casing main body section 315, to which the adjustor370 acting as the adjustment means is inserted, is adjusted such that,at the time at which the valve body 331 of the main regulating valve 330comes into close contact with the valve seat 332 of the main regulatingvalve 330 and closes the aperture 333, the valve body 341 of thepreliminary regulating valve 340 also comes into close contact with thevalve seat 342 of the preliminary regulating valve 340 and closes theaperture 343. The adjustor 370 thus adjusts the value of the pressureloss, which occurs at the preliminary regulating valve 340.

Each of the plunger 360 and the supporter 380 may be constituted of alight metal or a light metal alloy, such as aluminum or duralumin.Alternatively, each of the plunger 360 and the supporter 380 may beconstituted of a polyamide (PA), a polyacetal (POM), a polybutyleneterephthalate (PBT), or a polypropylene (PP), which is a crystallineresin. As another alternative, each of the plunger 360 and the supporter380 may be constituted of an acetal, a polycarbonate, oracrylonitrile-butadiene-styrene, which is a non-crystalline resin, thenon-crystalline resin having a surface coated with an epoxy resin or apolyamide resin. In cases where each of the plunger 360 and thesupporter 380 is constituted of one of the materials enumerated above,each of the plunger 360 and the supporter 380 is capable of being keptlight in weight and imparted with the resistance to the dimethyl ethergas.

Also, the casing 310 may be constituted of a polyamide (PA), apolyacetal (POM), a polybutylene terephthalate (PBT), or a polypropylene(PP), which is a crystalline resin. Alternatively, the casing 310 may beconstituted of an acetal, a polycarbonate, oracrylonitrile-butadiene-styrene, which is a non-crystalline resin, thenon-crystalline resin having a surface coated with an epoxy resin or apolyamide resin. In cases where the casing 310 is constituted of one ofthe materials enumerated above, the casing 310 is capable of being keptlight in weight and imparted with the resistance to the dimethyl ethergas.

The aforesaid epoxy resin, with which the surface of the non-crystallineresin described above may be coated, should preferably contain apolyphenol and epourea as principal constituents.

Also, the casing 310 (i.e., the casing main body section 315 and a coversection 316) may be constituted of a polyamide (PA), a polyacetal (POM),a polybutylene terephthalate (PBT), or a polypropylene (PP), which is acrystalline resin, and the casing 310 may be formed with the ultrasonicfusion bonding.

In cases where each of the plunger 360 and the supporter 380 is keptlight in weight, the response characteristics of the main regulatingvalve 330 and the preliminary regulating valve 340 with respect to thedisplacement of the diaphragm 320 are capable of being enhanced, and thechattering phenomenon is capable of being prevented from occurring.Specifically, since the plunger 360, to which the main regulating valve330 and the preliminary regulating valve 340 are fitted, and thesupporter 380 are secured to the diaphragm 320, if the weight of each ofthe plunger 360 and the supporter 380 is heavy, the responsecharacteristics of the main regulating valve 330 and the preliminaryregulating valve 340 with respect to the displacement of the diaphragm320 will become bad. Also, due to excessive inertia force, the quantityof the displacement of the diaphragm 320 will become larger than thequantity of the displacement in accordance with the pressure difference,and excessive displacement of the diaphragm 320 will then occur in thereverse direction. The excessive displacement of the diaphragm 320 willthus be iterated, and the vibration (the chattering phenomenon) will becaused to occur. Therefore, the weight of each of the constituent partsshould be kept as light as possible. Actually, in cases where each ofthe plunger 360 and the supporter 380 is constituted of aluminum,duralumin, or the resin, the chattering phenomenon does not occur.

Also, in cases where the casing 310 is constituted of the resin, thecasing 310 is capable of being kept light in weight and low in cost. Inparticular, in cases where the casing 310 is constituted of the resin,which is capable of being subjected to the ultrasonic bonding, theassembly operation is capable of being facilitated. Specifically, if theentire casing 310 is constituted of a metal or a diecast metal, theweight of the entire casing 310 will become heavy, and the cost of thecasing 310 will become high. Also, since it is necessary for theoperation for securing with screws to be performed, the assemblyoperation cannot be kept easy. In cases where the casing 310 isconstituted of the resin as described above, the casing 310 is capableof being kept light in weight and low in cost. Also, since the casing310 is capable of being formed with the ultrasonic bonding, theoperation for assembling the casing 310 is capable of being performedeasily.

If the members, such as the casing 310, the plunger 360, and thesupporter 380, which come into direct contact with the gas, areconstituted of a metal, in cases where the high-pressure gas isprimarily the dimethyl ether gas, or the like, which has the highdissolving characteristics, a slight amount of a metal ion will bedissolved out into the gas and will adversely affect the appliances towhich the gas having been subjected to the pressure regulation issupplied. From this point of view, each of the casing 310, the plunger360, and the supporter 380 should preferably be constituted of theresin.

Specifically, it is expected that the dimethyl ether gas is capable ofbeing used as the fuel for the solid oxide type fuel cells (SOFC's) andthe solid polymer type fuel cells (PEFC's). In both the cases of thesolid oxide type fuel cells (SOFC's) and the solid polymer type fuelcells (PEFC's), it is markedly undesirable that metal ions are presentin the dimethyl ether gas supplied as the fuel. Therefore, the aforesaidstructure constituted of the resin should preferably be employed.

In accordance with the movement of the diaphragm 320, the mainregulating valve 330 and the preliminary regulating valve 340 co-operatewith each other in order to reduce and regulate the unregulated pressureinto the predetermined regulated pressure regardless of the fluctuationin unregulated pressure. How the main regulating valve 330 and thepreliminary regulating valve 340 operate will be described hereinbelow.

Firstly, the gas having flowed from the gas introducing port 313 passesthrough the preliminary regulating valve 340, which is located at thestage prior to the main regulating valve 330, and the gas is subjectedto the preliminary pressure reduction. The gas having been subjected tothe preliminary pressure reduction passes through the aperture 343, i.e.through the space between the inside peripheral surface of the leadingend tube section 371 of the adjustor 370 and the outside peripheralsurface of the plunger 360, into the preliminary chamber 322. The gaswithin the preliminary chamber 322 then passes through the mainregulating valve 330, and the pressure of the gas is accurately reducedto the regulated pressure. The gas having the regulated pressure passesthrough the aperture 333 and the pressure regulating chamber 311 and isthen discharged through the gas discharging port 314.

The diaphragm 320 is supported by the plunger 360 and the supporter 380.The diaphragm 320 is kept at the position, at which the force due to thepressure difference between the regulated pressure and the atmosphericpressure and the urging force of the pressure regulating spring 351 arebalanced with each other. In cases where the regulated pressure variesin accordance with a variation in quantity of the gas discharged fromthe gas discharging port 314, the variation in unregulated pressure, andthe like, the quantity of the displacement of the diaphragm 320 variesin accordance with the variation in regulated pressure, and the positionof the plunger 360 varies. Also, the main regulating valve 330 and thepreliminary regulating valve 340 move in accordance with the variationin position of the plunger 360 and keep the regulated pressure at thepredetermined pressure. The urging force of the pressure regulatingspring 351 is capable of being varied by the adjustment of the positionof the pressure regulating screw 352 of the pressure setting section350, and the regulated pressure is thus capable of being set at anarbitrary pressure.

Also, the pressure reduction from the unregulated pressure to theregulated pressure is performed by the combination of the two regulatingvalves, i.e. the combination of the main regulating valve 330 and thepreliminary regulating valve 340. Therefore, the value of the pressureloss occurring at each of the two regulating valves 330 and 340 iscapable of being kept to be smaller than the value of the pressure loss,which occurs in cases where the pressure reduction is performed withonly one regulating valve. Accordingly, each of the space between thevalve body 331 and the valve seat 332 of the main regulating valve 330and the space between the valve body 341 and the valve seat 342 of thepreliminary regulating valve 340 is capable of being set to becomparatively large. As a result, reliable performance is capable ofbeing obtained in cases where the unregulated pressure is markedly high.Specifically, the reliable performance is capable of being obtained incases where the degree of the required pressure reduction is high, thevalve space between the valve body and the valve seat is set to bemarkedly small, and therefore a slight variation in valve space affectsthe regulated pressure.

Further, the valve body 331 of the main regulating valve 330 and thevalve body 341 of the preliminary regulating valve 340 are fitted ontothe plunger 360. Both the main regulating valve 330 and the preliminaryregulating valve 340 perform the valve opening and closing operations inaccordance with the deformation of the one diaphragm 320 and the onepressure regulating spring 351. Therefore, the response characteristicsof the main regulating valve 330 and the preliminary regulating valve340 with respect to the variation in unregulated pressure are capable ofbeing kept good. Also, with respect to marked fluctuation in unregulatedpressure, the follow-up speed is capable of being kept high, and theresponse characteristics are capable of being kept good. Therefore,reliable pressure regulation is capable of being performed.

Furthermore, each of the valve body 331 of the main regulating valve 330and the valve body 341 of the preliminary regulating valve 340 isconstituted of the elastic body, which is formed as the O-ring.Therefore, in cases where the gas having the high dissolvingcharacteristics, such as the dimethyl ether gas, is introduced into thepressure regulator 300, and each of the O-rings is brought into contactwith the gas having the high dissolving characteristics and undergoesswelling and expansion in volume, the variation in volume of each of theO-rings is restricted so as to occur only in the direction, which isnormal to the directions of valve opening and closing movements.Accordingly, the variation in pressure loss and the variation in gasflow rate due to the expansion in volume of each of the O-rings arecapable of being suppressed.

In the second embodiment described above, each of the valve body 331 ofthe main regulating valve 330 and the valve body 341 of the preliminaryregulating valve 340 is constituted of the elastic body, which is formedas the O-ring. Alternatively, each of the valve seat 332 of the mainregulating valve 330 and the valve seat 342 of the preliminaryregulating valve 340 may be constituted of the elastic body, which isformed as the O-ring. In such cases, each of the elastic body acting asthe valve seat 332 and the elastic body acting as the valve seat 342 islocated in a state in which the elastic body is controlled by aperipheral groove structure, or the like, such that the elastic body isprevented from deforming with respect to the directions of valve openingand closing movements. As another alternative, an elastic body otherthan the O-ring may be employed.

The results of experiments conducted for evaluating the pressureregulating effects of the second embodiment of the pressure regulator inaccordance with the present invention (i.e., the pressure regulator 300having the structure illustrated in FIG. 5) and the results ofexperiments conducted for evaluating the pressure regulating effects ofpressure regulators of comparative examples (i.e, the single-valve typepressure regulator 500 illustrated in FIG. 14 in the comparativeexamples in Measurement Examples 3 and 4 described below, and a pressureregulator comprising two single-valve type pressure regulators connectedin series in a different comparative example in Measurement Example 5described below) will be described hereinbelow with reference to FIG. 6,FIG. 7, FIG. 8, and FIG. 9. FIG. 6 is a graph showing the results ofmeasurement of a variation in regulated pressure, which results wereobtained with the pressure regulator 300 shown in FIG. 5 in cases wherean unregulated pressure of a high-pressure gas supplied to the pressureregulator 300 shown in FIG. 5 was altered, and the results ofmeasurement of a variation in regulated pressure, which results wereobtained with the single-valve type pressure regulator 500 of thecomparative example in cases where the unregulated pressure of thehigh-pressure gas supplied to the pressure regulator 500 of thecomparative example was altered. FIG. 7 is a graph showing the resultsof measurement of a variation in gas flow rate with respect to thepassage of time, which results were obtained with the pressure regulator300 shown in FIG. 5 in cases where a dimethyl ether gas was utilized asthe high-pressure gas supplied to the pressure regulator 300 shown inFIG. 5, and the results of measurement of a variation in gas flow ratewith respect to the passage of time, which results were obtained withthe pressure regulator 500 of the comparative example in cases where thedimethyl ether gas was utilized as the high-pressure gas supplied to thepressure regulator 500 of the comparative example. FIG. 8 is a graphshowing the results of measurement of a rise time occurring between whenintroduction of a high-pressure gas having an unregulated pressure intothe pressure regulator 300 shown in FIG. 5 was begun and when aregulated pressure obtained with the pressure regulator 300 shown inFIG. 5 became stable, which results were obtained in cases where theunregulated pressure was altered. FIG. 9 is a graph showing the resultsof measurement of a rise time occurring between when introduction of thehigh-pressure gas having the unregulated pressure into a pressureregulator of a different comparative example was begun and when theregulated pressure obtained with the pressure regulator of the differentcomparative example became stable, which results were obtained in caseswhere the unregulated pressure was altered.

MEASUREMENT EXAMPLE 3

In Measurement Example 3, measurement was made to find a variation inregulated pressure in cases where an unregulated pressure of ahigh-pressure gas (an inert gas) supplied to each of the pressureregulators was altered. The results of the measurement obtained with thepressure regulator 300 of FIG. 5 in the example in accordance with thepresent invention are indicated by the solid line in FIG. 6. Also, theresults of the measurement obtained with the single-valve type pressureregulator 500 of FIG. 14 in the comparative example are indicated by thebroken line in FIG. 6.

In both the example in accordance with the present invention and thecomparative example, the regulated pressure was set by the adjustment ofthe pressure regulating screw 352 of the pressure setting section 350 orthe pressure regulating screw 509 b of the pressure setting section 509,such that, when the unregulated pressure was equal to 400 kPa(corresponding to the vapor pressure of the dimethyl ether gas at atemperature of approximately 23° C.), the regulated pressure becameequal to 50 kPa. At this time, the gas flow rate was equal to 80 mL/min.

As indicated by the solid line in the graph of FIG. 6, with the pressureregulator 300 of FIG. 5 in accordance with the present invention, incases where the unregulated pressure was altered over the range of 50kPa to 2000 kPa (corresponding to the range of the variation in vaporpressure of the dimethyl ether gas at temperatures ranging fromapproximately 0° C. to approximately 80° C.), the pressure regulationcharacteristics with respect to the low unregulated pressure wereidentical with the pressure regulation characteristics of thesingle-valve type pressure regulator 500 of FIG. 14 in the comparativeexample. However, with the pressure regulator 300 of FIG. 5 inaccordance with the present invention, as the unregulated pressurebecame high, the regulated pressure did not vary and was kept atapproximately the set value (50 kPa), and the predetermined regulatedpressure was kept.

However, as indicated by the broken line in the graph of FIG. 6, withthe single-valve type pressure regulator 500 of FIG. 14 in thecomparative example, in cases where the unregulated pressure fell withinthe region lower than 400 kPa, the regulated pressure was higher thanthe set value (50 kPa). Also, in cases where the unregulated pressurefell within the region higher than 400 kPa, the regulated pressurevaried such that the regulated pressure became lower than the set value(50 kPa), and such that, as the unregulated pressure became high, theregulated pressure became low as a whole. In this manner, with thesingle-valve type pressure regulator 500 of FIG. 14 in the comparativeexample, the regulated pressure was not capable of being kept at thepredetermined pressure.

MEASUREMENT EXAMPLE 4

In Measurement Example 4, measurement was made to find a variation ingas flow rate with respect to the passage of time in cases where adimethyl ether gas, which was a typical gas causing an elastic material(a rubber material) to swell, was utilized as the high-pressure gassupplied to each of the pressure regulators. The results of themeasurement obtained with the pressure regulator 300 of FIG. 5 in theexample in accordance with the present invention are indicated by thesolid line in FIG. 7. Also, the results of the measurement obtained withthe single-valve type pressure regulator 500 of FIG. 14 in thecomparative example are indicated by the broken line in FIG. 7. Theinitial flow rate of the dimethyl ether gas was equal to 80 mL/min. Thetest was conducted at a temperature, at which the vapor pressure wasequal to 400 kPa.

As indicated by the solid line in the graph of FIG. 7, with the pressureregulator 300 of FIG. 5 in accordance with the present invention, incases where a period of time of as long as 120 minutes had elapsed, theflow rate of the discharged gas did not vary and was kept at the initialflow rate. It was capable of being confirmed that, with the pressureregulator 300 of FIG. 5 in accordance with the present invention, eventhough the O-rings were subjected to the swelling due to the contactwith the gas, adverse effects upon the gas flow rate did not occur.

However, as indicated by the broken line in the graph of FIG. 7, withthe single-valve type pressure regulator 500 of FIG. 14 in thecomparative example, due to a variation in valve space accompanying theswelling of the valve seat 506 b constituted of the elastic body, thegas flow rate begun becoming low at the time at which a period of timeof approximately 15 minutes had elapsed after the start of themeasurement. Thereafter, the gas flow rate became markedly low with thepassage of time. At the time at which a period of time of approximately60 minutes had elapsed after the start of the measurement, the gas flowrate became 0 (zero), and the gas could not be discharged any more.

MEASUREMENT EXAMPLE 5

In Measurement Example 5, a cock was installed at a stage prior to thegas introducing port 313 of the pressure regulator 300 of FIG. 5 or thegas introducing port of the pressure regulator in the differentcomparative example. Also, the cock was quickly operated from a closedstate into an open state, and the gas introduction was thus begun. Atthis time, measurement was made to find a rise time occurring betweenwhen the introduction of the high-pressure gas having an unregulatedpressure into the pressure regulator 300 shown in FIG. 5 or the pressureregulator of the different comparative example was begun and when aregulated pressure obtained with the pressure regulator became stable,while the unregulated pressure was being set at various values. Theresults of the measurement obtained with the pressure regulator 300 ofFIG. 5 in the example in accordance with the present invention are shownin FIG. 8. Also, the results of the measurement obtained with thepressure regulator of the different comparative example are shown inFIG. 9. The pressure regulator of the different comparative examplecomprised a combination of a single-valve type pressure regulator forhigh pressures and a single-valve type pressure regulator for lowpressures, which pressure regulators were connected in series. Thepressure regulator of the different comparative example had beenreported to be capable of accurately keeping the regulated pressure withrespect to a wide unregulated pressure range.

As clear from the graph of FIG. 8, with the pressure regulator 300 ofFIG. 5 in accordance with the present invention, in cases where theunregulated pressure fell within the high pressure range of at least 400kPa, the rise time was as short as 0.4 second, the regulated pressurequickly became stable, and high response characteristics were obtained.Also, as the unregulated pressure became high, the rise time becameshorter, and the regulated pressure became stable more quickly. It wasthus confirmed that, with the pressure regulator 300 of FIG. 5 inaccordance with the present invention, a high follow-up speed withrespect to marked fluctuation in unregulated pressure was capable ofbeing obtained.

However, as shown in FIG. 9, with the pressure regulator of thedifferent comparative example described above, a period of time ofseveral seconds occurred before the regulated pressure became stablewith the operation of each of the two single-valve type pressureregulators.

The response characteristics were thus worse than the responsecharacteristics of the pressure regulator 300 of FIG. 5 in accordancewith the present invention. Also, as the unregulated pressure becamehigh, the rise time was apt to become long.

A third embodiment of the pressure regulator in accordance with thepresent invention will be described hereinbelow. FIG. 10 is a sectionalview showing a third embodiment of the pressure regulator in accordancewith the present invention.

With reference to FIG. 10, a pressure regulator 400, which is the thirdembodiment of the pressure regulator in accordance with the presentinvention, is used for the stabilization of fuel supply to solid oxidetype fuel cells (SOFC's) and solid polymer type fuel cells (PEFC's).Also, a dimethyl ether gas is utilized as the high-pressure gas to besupplied to the pressure regulator 400. The pressure regulator 400comprises a first-stage governor system 420, which is provided with afirst regulating valve 421 for reducing an unregulated pressure of theintroduced gas into an intermediate pressure. The pressure regulator 400also comprises a second-stage governor system 430, which is providedwith a second regulating valve 431 for reducing the intermediatepressure to a regulated pressure.

Also, the first-stage governor system 420 and the second-stage governorsystem 430 are located such that the direction of the displacement of afirst diaphragm 422 for operating the first regulating valve 421 of thefirst-stage governor system 420 (i.e., the directions of the valveopening and closing operations of the first regulating valve 421) andthe direction of the displacement of a second diaphragm 432 foroperating the second regulating valve 431 of the second-stage governorsystem 430 (i.e., the directions of the valve opening and closingoperations of the second regulating valve 431) intersect with eachother.

Specifically, the first-stage governor system 420 comprises the firstdiaphragm 422, which partitions off a part of a region within a casing410 into a first pressure regulating chamber 424 and a first atmosphericchamber 425. The first-stage governor system 420 also comprises a gasintroducing port 411, through which the high-pressure gas having theunregulated pressure is introduced into the first-stage governor system420. The first-stage governor system 420 further comprises the firstregulating valve 421, which operates by being interlocked with the firstdiaphragm 422. The first regulating valve 421 performs operations foropening and closing a gas flow path 426, through which the gasintroducing port 411 and the first pressure regulating chamber 424communicate with each other. The first regulating valve 421 thusperforms first-stage pressure reduction and regulation for reducing theunregulated pressure of the high-pressure gas within the gas introducingport 411 to the intermediate pressure. The first-stage governor system420 still further comprises a first plunger 423, by which the firstdiaphragm 422 and the first regulating valve 421 are linked andinterlocked with each other. The first-stage governor system 420 alsocomprises a first pressure setting section 427 for adjusting thequantity of the displacement of the first diaphragm 422.

The first pressure regulating chamber 424 is capable of relaxingpressure vibration of the gas, which has passed through the firstregulating valve 421. The first diaphragm 422 receives the intermediatepressure within the first pressure regulating chamber 424 and is thusdisplaced. The first diaphragm 422 operates the first regulating valve421 via the first plunger 423.

The second-stage governor system 430 comprises the second diaphragm 432,which partitions off a part of the region within the casing 410 into asecond pressure regulating chamber 434 and a second atmospheric chamber435. The second-stage governor system 430 also comprises the secondregulating valve 431, which operates by being interlocked with thesecond diaphragm 432. The second regulating valve 431 performsoperations for opening and closing an opening of a gas flow path 436,through which the first pressure regulating chamber 424 and the secondpressure regulating chamber 434 communicate with each other. The secondregulating valve 431 thus performs second-stage pressure reduction andregulation for reducing the intermediate pressure within the firstpressure regulating chamber 424 to the regulated pressure. Thesecond-stage governor system 430 further comprises a second plunger 433,by which the second diaphragm 432 and the second regulating valve 431are linked and interlocked with each other. The second-stage governorsystem 430 still further comprises a second pressure setting section 437for adjusting the quantity of the displacement of the second diaphragm432. The second-stage governor system 430 also comprises a gasdischarging port 412, through which the gas having been subjected to thepressure regulation within the second pressure regulating chamber 434and having the regulated pressure is discharged.

The second pressure regulating chamber 434 is capable of relaxingpressure vibration of the gas, which has passed through the secondregulating valve 431. The second diaphragm 432 receives the regulatedpressure within the second pressure regulating chamber 434 and is thusdisplaced. The second diaphragm 432 operates the second regulating valve431 via the second plunger 433.

The first plunger 423 and the second plunger 433 are located such thatthe first plunger 423 and the second plunger 433 extend in directionswhich intersect at right angles with each other. A part of the firstplunger 423 is inserted for sliding movement into the gas flow path 426extending from the gas introducing port 411 to the first pressureregulating chamber 424. A valve body 421 a of the first regulating valve421, which is fitted onto a region in the vicinity of an end of thefirst plunger 423, is located within the gas introducing port 411. Also,a part of the second plunger 433 is inserted for sliding movement intothe gas flowpath 436 extending from the first pressure regulatingchamber 424 to the second pressure regulating chamber 434. A valve body431 a of the second regulating valve 431, which is fitted onto a regionin the vicinity of an end of the second plunger 433, is located withinthe first pressure regulating chamber 424.

Further, each of the valve body 421 a of the first regulating valve 421and the valve body 431 a of the second regulating valve 431 isconstituted of an elastic body formed from a urethane type rubbermaterial, which elastic body takes on the form of an O-ring. The valvebody 421 a constituted of the elastic body is supported in a peripheralgroove section of the first plunger 423, such that the valve body 421 adoes not undergo swelling deformation in the directions of valve openingand closing movements, i.e. such that the direction of the swellingdeformation of the valve body 421 a becomes different from thedirections of valve opening and closing operations (in this embodiment,such that the direction of the swelling deformation of the valve body421 a is normal to the directions of valve opening and closingoperations). Also, the valve body 431 a constituted of the elastic bodyis supported in a peripheral groove section of the second plunger 433,such that the valve body 431 a does not undergo swelling deformation inthe directions of valve opening and closing movements, i.e. such thatthe direction of the swelling deformation of the valve body 431 abecomes different from the directions of valve opening and closingoperations (in this embodiment, such that the direction of the swellingdeformation of the valve body 431 a is normal to the directions of valveopening and closing operations). Therefore, the dimethyl ether gas, orthe like, which will have adverse effects, such as swelling effects,upon the elastic body, is capable of being used as the high-pressuregas.

The first diaphragm 422 of the first-stage governor system 420 has anoutside diameter smaller than the outside diameter of the seconddiaphragm 432 of the second-stage governor system 430. The pressurereceiving area of the first diaphragm 422 of the first-stage governorsystem 420 is thus set to be smaller than the pressure receiving area ofthe second diaphragm 432 of the second-stage governor system 430.

The structure of the pressure regulator 400 will hereinbelow bedescribed in more detail. The casing 410 described above comprises acasing main body section 410 a, a first cover section 410 b of thefirst-stage governor system 420, and a second cover section 410 c of thesecond-stage governor system 430.

A subsection of the casing main body section 410 a, at which subsectionthe first-stage governor system 420 is located, is provided with adepressed region, which acts as the gas introducing port 411, and adepressed region, which is formed on the side opposite to the gasintroducing port 411 and acts as the first pressure regulating chamber424. The gas flow path 426, through which the gas introducing port 411and the first pressure regulating chamber 424 communicate with eachother, is formed through the center areas of the two depressed regions.The first cover section 410 b has a hollow inside region, which acts asthe first atmospheric chamber 425. The first cover section 410 b isjoined to the casing main body section 410 a with the first diaphragm422 intervening between the first cover section 410 b and the casingmain body section 410 a. In this manner, the first pressure regulatingchamber 424 and the first atmospheric chamber 425 are partitioned offfrom each other by the first diaphragm 422.

Also, a subsection of the casing main body section 410 a, at whichsubsection the second-stage governor system 430 is located, is providedwith a depressed region, which acts as the second pressure regulatingchamber 434. The gas discharging port 412, which is open to theexterior, is formed along a side of the depressed region. Further, thegas flow path 436, through which the second pressure regulating chamber434 and the first pressure regulating chamber 424 communicate with eachother, is formed through the center area of the bottom part defining thedepressed region. The second cover section 410 c has a hollow insideregion, which acts as the second atmospheric chamber 435. The secondcover section 410 c is joined to the casing main body section 410 a withthe second diaphragm 432 intervening between the second cover section410 c and the casing main body section 410 a. In this manner, the secondpressure regulating chamber 434 and the second atmospheric chamber 435are partitioned off from each other by the second diaphragm 432. Thefirst pressure regulating chamber 424 has a certain level of volume andperforms relaxation of pressure vibration of the gas, which has passedthrough the first regulating valve 421. Also, the second pressureregulating chamber 434 has a certain level of volume and performsrelaxation of pressure vibration of the gas, which has passed throughthe second regulating valve 431.

As described above, the first diaphragm 422 and the second diaphragm 432have the different outside diameters. However, the first diaphragm 422receives the intermediate pressure within the first pressure regulatingchamber 424 and is thus capable of undergoing the elastic displacementin accordance with the pressure difference between the first pressureregulating chamber 424 and the first atmospheric chamber 425. Also, thesecond diaphragm 432 receives the regulated pressure within the secondpressure regulating chamber 434 and is thus capable of undergoing theelastic displacement in accordance with the pressure difference betweenthe second pressure regulating chamber 434 and the second atmosphericchamber 435. The center area of the first diaphragm 422 is linked andsecured to the first plunger 423, which is located on the side of thecasing main body section 410 a, and a first supporter 428, which islocated on the side of the first cover section 410 b. The first plunger423 and the first supporter 428 are capable of moving together in theaxial direction in accordance with the displacement of the firstdiaphragm 422. Also, the center area of the second diaphragm 432 islinked and secured to the second plunger 433, which is located on theside of the casing main body section 410 a, and a second supporter 438,which is located on the side of the second cover section 410 c. Thesecond plunger 433 and the second supporter 438 are capable of movingtogether in the axial direction in accordance with the displacement ofthe second diaphragm 432.

The first plunger 423 is provided with a shaft section 423 a, whichextends in a rod-like shape at the end region of the first plunger 423.The shaft section 423 a is provided with a peripheral groove section,which is formed at a position in the vicinity of the end of the shaftsection 423 a. The valve body 421 a of the first regulating valve 421,which valve body is constituted of the O-ring (i.e., the elastic body),is fitted into the peripheral groove section of the shaft section 423 a.Also, the second plunger 433 is provided with a shaft section 433 a,which extends in a rod-like shape at the end region of the secondplunger 433. The shaft section 433 a is provided with a peripheralgroove section, which is formed at a position in the vicinity of the endof the shaft section 433 a. The valve body 431 a of the secondregulating valve 431, which valve body is constituted of the O-ring(i.e., the elastic body), is fitted into the peripheral groove sectionof the shaft section 433 a.

One end section of a pressure regulating spring 427 a of the firstpressure setting section 427, which is located within a tubular sectionof the first cover section 410 b, is brought into abutment with a flangesection of the first supporter 428. The first supporter 428 thusreceives the pressure setting load. The other end section of thepressure regulating spring 427 a is brought into abutment with a firstpressure regulating screw (adjustor) 427 b, which is engaged by threadswith an inside wall of the tubular section of the first cover section410 b such that the position of the first pressure regulating screw 427b is capable of being adjusted. The urging force of the pressureregulating spring 427 a acting upon the first diaphragm 422 is adjustedin accordance with the adjustment of the position of the first pressureregulating screw 427 b with respect to the axial direction of thetubular section of the first cover section 410 b. A center area of thefirst pressure regulating screw 427 b has a communication through-hole427 c, which passes through the center area of the first pressureregulating screw 427 b in the axial direction of the first pressureregulating screw 427 b. Through the communication through-hole 427 c ofthe first pressure regulating screw 427 b, the first atmospheric chamber425 is open to the ambient atmosphere.

Also, one end section of a pressure regulating spring 437 a of thesecond pressure setting section 437, which is located within a tubularsection of the second cover section 410 c, is brought into abutment witha flange section of the second supporter 438. The second supporter 438thus receives the pressure setting load. The other end section of thepressure regulating spring 437 a is brought into abutment with a secondpressure regulating screw (adjustor) 437 b, which is engaged by threadswith an inside wall of the tubular section of the second cover section410 c such that the position of the second pressure regulating screw 437b is capable of being adjusted. The urging force of the pressureregulating spring 437 a acting upon the second diaphragm 432 is adjustedin accordance with the adjustment of the position of the second pressureregulating screw 437 b with respect to the axial direction of thetubular section of the second cover section 410 c. A center area of thesecond pressure regulating screw 437 b has a communication through-hole437 c, which passes through the center area of the second pressureregulating screw 437 b in the axial direction of the second pressureregulating screw 437 b. Through the communication through-hole 437 c ofthe second pressure regulating screw 437 b, the second atmosphericchamber 435 is open to the ambient atmosphere.

The gas introducing port 411 of the casing main body section 410 a isconnected to a connector (not shown) for introducing the high-pressuregas, such as the dimethyl ether gas, which is supplied from a gascylinder, or the like. The gas flow path 426, through which the gasintroducing port 411 and the first pressure regulating chamber 424communicate with each other, is opened and closed by the firstregulating valve 421. The shaft section 423 a of the first plunger 423is inserted for sliding movement into gas flow path 426. The valve body421 a of the first regulating valve 421 stands facing the gasintroducing port 411. An area of a wall of the casing main body section410 a, which area stands facing the gas introducing port 411 and islocated in the vicinity of and around the gas flow path 426, acts as avalve seat 421 b of the first regulating valve 421.

In accordance with the movement of the first plunger 423, the valve body421 a of the first regulating valve 421 comes into close contact withthe valve seat 421 b and closes the gas flow path 426. In cases wherethe valve body 421 a of the first regulating valve 421 moves away fromthe valve seat 421 b and opens the gas flow path 426 in accordance withthe movement of the first plunger 423, a quantity of the gas inaccordance with the quantity of the opening of the gas flow path 426passes through the space between the inside peripheral surface of thewall defining the gas flow path 426 and the outside peripheral surfaceof the first plunger 423 and flows from the gas introducing port 411into the first pressure regulating chamber 424.

Also, the gas flow path 436, which extends through the center area ofthe bottom part of the second pressure regulating chamber 434 of thecasing main body section 410 a, is opened and closed by the secondregulating valve 431. The shaft section 433 a of the second plunger 433is inserted for sliding movement into the gas flow path 436. The valvebody 431 a of the second regulating valve 431 stands facing the firstpressure regulating chamber 424. An area of a wall of the casing mainbody section 410 a, which area stands facing the first pressureregulating chamber 424 and is located in the vicinity of and around thegas flow path 436, acts as a valve seat 431 b of the second regulatingvalve 431.

In accordance with the movement of the second plunger 433, the valvebody 431 a of the second regulating valve 431 comes into close contactwith the valve seat 431 b and closes the gas flow path 436. In caseswhere the valve body 431 a of the second regulating valve 431 moves awayfrom the valve seat 431 b and opens the gas flow path 436 in accordancewith the movement of the second plunger 433, a quantity of the gas inaccordance with the quantity of the opening of the gas flow path 436passes through the space between the inside peripheral surface of thewall defining the gas flow path 436 and the outside peripheral surfaceof the second plunger 433 and flows from the first pressure regulatingchamber 424 into the second pressure regulating chamber 434.

Each of the first plunger 423, the second plunger 433, the firstsupporter 428, and the second supporter 438 may be constituted of alight metal or a light metal alloy, such as aluminum or duralumin.Alternatively, each of the first plunger 423, the second plunger 433,the first supporter 428, and the second supporter 438 may be constitutedof a polyamide (PA), a polyacetal (POM), a polybutylene terephthalate(PBT), or a polypropylene (PP), which is a crystalline resin. As anotheralternative, each of the first plunger 423, the second plunger 433, thefirst supporter 428, and the second supporter 438 may be constituted ofan acetal, a polycarbonate, or acrylonitrile-butadiene-styrene, which isa non-crystalline resin, the non-crystalline resin having a surfacecoated with an epoxy resin or a polyamide resin. In cases where each ofthe first plunger 423, the second plunger 433, the first supporter 428,and the second supporter 438 is constituted of one of the materialsenumerated above, each of the first plunger 423, the second plunger 433,the first supporter 428, and the second supporter 438 is capable ofbeing kept light in weight and imparted with the resistance to thedimethyl ether gas.

Also, the casing 410 (i.e., the casing main body section 410 a, thefirst cover section 410 b, and the second cover section 410 c) may beconstituted of a resin. Examples of the preferable resins include thosedescribed above for the casing 310 in the second embodiment.

In cases where each of the first plunger 423, the second plunger 433,the first supporter 428, and the second supporter 438 is kept light inweight, the response characteristics of the first regulating valve 421with respect to the displacement of the first diaphragm 422 and theresponse characteristics of the second regulating valve 431 with respectto the displacement of the second diaphragm 432 are capable of beingenhanced, and the chattering phenomenon is capable of being preventedfrom occurring. Specifically, the first plunger 423, to which the firstregulating valve 421 is fitted, and the first supporter 428 are securedto the first diaphragm 422. Also, the second plunger 433, to which thesecond regulating valve 431 is fitted, and the second supporter 438 aresecured to the second diaphragm 432. Therefore, if the weight of each ofthe first plunger 423, the second plunger 433, the first supporter 428,and the second supporter 438 is heavy, the response characteristics ofthe first regulating valve 421 with respect to the displacement of thefirst diaphragm 422 and the response characteristics of the secondregulating valve 431 with respect to the displacement of the seconddiaphragm 432 will become bad. Also, due to excessive inertia force, thequantity of the displacement of each of the first diaphragm 422 and thesecond diaphragm 432 will become larger than the quantity of thedisplacement in accordance with the pressure difference, and excessivedisplacement of each of the first diaphragm 422 and the second diaphragm432 will then occur in the reverse direction. The excessive displacementof the each of the first diaphragm 422 and the second diaphragm 432 willthus be iterated, and the vibration (the chattering phenomenon) will becaused to occur. Therefore, the weight of each of the constituent partsshould be kept as light as possible. Actually, in cases where each ofthe first plunger 423, the second plunger 433, the first supporter 428,and the second supporter 438 is constituted of aluminum, duralumin, orthe resin, the chattering phenomenon does not occur.

Also, in cases where the casing 410 is constituted of the resin, thecasing 410 is capable of being kept light in weight and low in cost. Inparticular, in cases where the casing 410 is constituted of the resin,which is capable of being subjected to the ultrasonic bonding, theassembly operation is capable of being facilitated. Specifically, if theentire casing 410 is constituted of a metal or a diecast metal, theweight of the entire casing 410 will become heavy, and the cost of thecasing 410 will become high. Also, since it is necessary for theoperation for securing with screws to be performed, the assemblyoperation cannot be kept easy. In cases where the casing 410 isconstituted of the resin as described above, the casing 410 is capableof being kept light in weight and low in cost. Also, since the casing410 is capable of being formed with the ultrasonic bonding, theoperation for assembling the casing 410 is capable of being performedeasily.

If the members, such as the casing 410, the first plunger 423, thesecond plunger 433, the first supporter 428, and the second supporter438, which come into direct contact with the gas, are constituted of ametal, in cases where the high-pressure gas is primarily the dimethylether gas, or the like, which has the high dissolving characteristics, aslight amount of a metal ion will be dissolved out into the gas and willadversely affect the appliances to which the gas having been subjectedto the pressure regulation is supplied. From this point of view, each ofthe casing 410, the first plunger 423, the second plunger 433, the firstsupporter 428, and the second supporter 438 should preferably beconstituted of the resin.

Specifically, it is expected that the dimethyl ether gas is capable ofbeing used as the fuel for the solid oxide type fuel cells (SOFC's) andthe solid polymer type fuel cells (PEFC's). In both the cases of thesolid oxide type fuel cells (SOFC's) and the solid polymer type fuelcells (PEFC's), it is markedly undesirable that metal ions are presentin the dimethyl ether gas supplied as the fuel. Therefore, the aforesaidstructure constituted of the resin should preferably be employed.

With the first-stage governor system 420, in accordance with thedisplacement of the first diaphragm 422, the first regulating valve 421operates in order to reduce and regulate the unregulated pressure intothe intermediate pressure regardless of the fluctuation in unregulatedpressure. Also, with the second-stage governor system 430, in accordancewith the displacement of the second diaphragm 432, the second regulatingvalve 431 operates in order to reduce and regulate the intermediatepressure into the predetermined regulated pressure. The unregulatedpressure is thus reduced and regulated into the predetermined regulatedpressure via the intermediate pressure regardless of the fluctuation inunregulated pressure. How the first-stage governor system 420 and thesecond-stage governor system 430 operate will be described hereinbelow.

Firstly, the gas having flowed from the gas introducing port 411 passesthrough the first regulating valve 421 and flows through the gas flowpath 426 into the first pressure regulating chamber 424, and theunregulated pressure of the gas is thus reduced to the intermediatepressure. The gas having the intermediate pressure within the firstpressure regulating chamber 424 passes through the second regulatingvalve 431 and flows through the gas flow path 436 into the secondpressure regulating chamber 434, and the intermediate pressure is thusreduced to the regulated pressure. The gas having the regulated pressureis discharged through the gas discharging port 412.

The first diaphragm 422 is supported by the first plunger 423 and thefirst supporter 428. The first diaphragm 422 is kept at the position, atwhich the force due to the pressure difference between the intermediatepressure and the atmospheric pressure and the urging force of thepressure regulating spring 427 a are balanced with each other. Also, thesecond diaphragm 432 is supported by the second plunger 433 and thesecond supporter 438.

The second diaphragm 432 is kept at the position, at which the force dueto the pressure difference between the regulated pressure and theatmospheric pressure and the urging force of the pressure regulatingspring 437 a are balanced with each other. In cases where theintermediate pressure or the regulated pressure varies in accordancewith the variation in unregulated pressure, a variation in quantity ofthe gas discharged from the gas discharging port 412, and the like, thequantity of the displacement of the first diaphragm 422 or the quantityof the displacement of the second diaphragm 432 varies in accordancewith the variation in intermediate pressure or the regulated pressure.The first plunger 423 and the second plunger 433 move in accordance withthe variation in quantity of the displacement. Also, the firstregulating valve 421 and the second regulating valve 431 perform thevalve opening and closing operations in accordance with the movements ofthe first plunger 423 and the second plunger 433 and keep theintermediate pressure and the regulated pressure at the predeterminedvalues. The urging force of the pressure regulating spring 427 a iscapable of being varied by the adjustment of the position of the firstpressure regulating screw 427 b of the first pressure setting section427, and the intermediate pressure is thus capable of being set at anarbitrary pressure. Also, the urging force of the pressure regulatingspring 437 a is capable of being varied by the adjustment of theposition of the second pressure regulating screw 437 b of the secondpressure setting section 437, and the regulated pressure is thus capableof being set at an arbitrary pressure.

Also, each of the valve body 421 a of the first regulating valve 421 andthe valve body 431 a of the second regulating valve 431 is constitutedof the elastic body, which is formed as the O-ring. Therefore, in caseswhere the gas having the high dissolving characteristics, such as thedimethyl ether gas, is introduced into the pressure regulator 400, andeach of the O-rings is brought into contact with the gas having the highdissolving characteristics and undergoes swelling and expansion involume, the variation in volume of each of the O-rings is restricted soas to occur only in the direction, which is normal to the directions ofvalve opening and closing movements. Accordingly, the variation inpressure regulation and the variation in gas flow rate due to theexpansion in volume of each of the O-rings are capable of beingsuppressed.

Further, since the first-stage governor system 420 and the second-stagegovernor system 430 are located in the orientations which intersect atright angles with each other, the gas flow paths are capable of beingkept simple and small in size. The first diaphragm 422 having a smalloutside diameter enables the size of the entire pressure regulator 400to be reduced even further. Furthermore, the accuracy with which thepressure regulation to the regulated pressure is conducted ultimately iscapable of being obtained with the operation of the second diaphragm432. Specifically, the pressure reduction from the unregulated pressureto the regulated pressure is performed in two stages by the firstregulating valve 421 and the second regulating valve 431. Therefore, theextent of the pressure reduction occurring at each of the two regulatingvalves 421 and 431 is capable of being kept to be smaller than theextent of the pressure reduction, which occurs in cases where thepressure reduction is performed with only one regulating valve.Accordingly, the problems are capable of being prevented from occurringin that, due to the high degree of the required pressure reduction, thevalve space between the valve body and the valve seat is set to bemarkedly small. As a result, reliable performance is capable of beingobtained.

In the third embodiment described above, each of the valve body 421 a ofthe first regulating valve 421 and the valve body 431 a of the secondregulating valve 431 is constituted of the elastic body, which is formedas the O-ring. Alternatively, each of the valve seat 421 b of the firstregulating valve 421 and the valve seat 431 b of the second regulatingvalve 431 may be constituted of the elastic body, which is formed as theO-ring. In such cases, each of the elastic body acting as the valve seat421 b and the elastic body acting as the valve seat 431 b is located ina state in which the elastic body is controlled by a peripheral groovestructure, or the like, such that the elastic body is prevented fromdeforming with respect to the directions of valve opening and closingmovements. As another alternative, an elastic body other than the O-ringmay be employed.

The results of experiments conducted for evaluating the pressureregulating effects of the third embodiment of the pressure regulator inaccordance with the present invention (i.e., the pressure regulator 400having the structure illustrated in FIG. 10) will be describedhereinbelow with reference to FIG. 11, FIG. 12, and FIG. 13. FIG. 11 isa graph showing the results of measurement of a variation in regulatedpressure, which results were obtained with the pressure, regulator shownin FIG. 10 in cases where an unregulated pressure of a high-pressure gassupplied to the pressure regulator shown in FIG. 10 was altered. FIG. 12is a graph showing the results of measurement of a variation in outletflow rate, which results were obtained with the pressure regulator shownin FIG. 10 in cases where an unregulated pressure of a high-pressure gassupplied to the pressure regulator shown in FIG. 10 was altered. FIG. 13is a graph showing the results of measurement of a variation inregulated pressure, which results were obtained with the pressureregulator shown in FIG. 10 in cases where an outlet flow rate in thepressure regulator shown in FIG. 10 was altered.

As the fundamental setting, the pressure regulator 400 was set suchthat, in cases where the unregulated pressure was equal to 400 kPa, theintermediate pressure became equal to 110 kPa, the regulated pressurebecame equal to 50 kPa, and the flow rate became equal to 80 mL/min. Inthe experiments, an N₂ gas (which was one of inert gases) was used.

MEASUREMENT EXAMPLE 6

In Measurement Example 6, measurement was made to find a variation inregulated pressure in cases where an unregulated pressure was alteredover the range of 200 kPa to 2000 kPa. The results of the measurementobtained with the pressure regulator 400 of FIG. 10 in the example inaccordance with the present invention are shown in the graph of FIG. 11.As clear from FIG. 11, the regulated pressure did not vary with respectto the variation in unregulated pressure, and the regulated pressureequal to the set pressure of 50 kPa was capable of being obtainedreliably.

The aforesaid range of the variation in unregulated pressurecorresponded to the range of the variation in vapor pressure of thedimethyl ether gas at temperatures ranging from approximately 0° C. toapproximately 80° C.)

MEASUREMENT EXAMPLE 7

In Measurement Example 7, measurement was made to find a variation inoutlet flow rate in cases where an unregulated pressure was altered overthe range of 200 kPa to 2000 kPa. The results of the measurementobtained with the pressure regulator 400 of FIG. 10 in the example inaccordance with the present invention are shown in the graph of FIG. 12.As clear from FIG. 12, the outlet flow rate did not vary with respect tothe variation in unregulated pressure, and the gas discharging rateequal to the set flow rate of 80 mL/min was capable of being obtainedreliably.

MEASUREMENT EXAMPLE 8

In Measurement Example 8, measurement was made to find a variation inregulated pressure in cases where an unregulated pressure was set at 400kPa (corresponding to the vapor pressure of the dimethyl ether gas at atemperature of approximately 23° C.), and the outlet flow rate (i.e.,the gas discharging rate) was altered over the range of 10 mL/min to 100mL/min. The results of the measurement obtained with the pressureregulator 400 of FIG. 10 in the example in accordance with the presentinvention are shown in the graph of FIG. 13. As clear from FIG. 13, theregulated pressure did not vary with respect to the variation in outletflow rate, and the regulated pressure equal to the set pressure of 50kPa was capable of being obtained reliably.

1. A pressure regulator, comprising: i) a gas introducing port, throughwhich a high-pressure gas having an unregulated pressure is introducedinto the pressure regulator, ii) a main regulating valve, which reducesthe unregulated pressure of the high-pressure gas to a regulatedpressure, a pressure loss occurring at the main regulating valve, iii) apressure regulating chamber for relaxing pressure vibration of the gas,which has passed through the main regulating valve, iv) a diaphragm,which partitions off the pressure regulating chamber and an atmosphericchamber from each other, and which receives the regulated pressurewithin the pressure regulating chamber and is thereby displaced, v) aplunger, which interlocks the diaphragm and the main regulating valvewith each other, vi) a pressure setting section for adjusting a quantityof the displacement of the diaphragm, vii) a gas discharging port,through which the gas having the regulated pressure is discharged fromthe pressure regulator, viii) a subsidiary regulating valve, whichoperates by being interlocked with the main regulating valve through theplunger and which reduces the unregulated pressure of the high-pressuregas to the regulated pressure, a pressure loss occurring at thesubsidiary regulating valve, the subsidiary regulating valve beinglocated such that the force, which accompanies the pressure lossoccurring at the subsidiary regulating valve and which the subsidiaryregulating valve receives, cancels the force, which accompanies thepressure loss occurring at the main regulating valve and which acts uponthe plunger, and ix) adjustment means, which is capable of adjusting avalue of the pressure loss occurring at the subsidiary regulating valve,the adjustment means being adjusted such that the value of the pressureloss, which the main regulating valve receives, and the value of thepressure loss, which the subsidiary regulating valve receives, becomeequal to each other.
 2. A pressure regulator as defined in claim 1wherein a valve body of the main regulating valve and a valve body ofthe subsidiary regulating valve are located on the plunger, one of thetwo valve bodies is located on the unregulated pressure side, and theother valve body is located on the regulated pressure side.
 3. Apressure regulator as defined in claim 1 wherein the adjustment means iscapable of adjusting the value of the pressure loss, which occurs at thesubsidiary regulating valve, with an operation for varying a position ofa valve seat of the subsidiary regulating valve with respect to amovement of the plunger.
 4. A pressure regulator as defined in claim 1wherein the adjustment means is constituted of a duplex-valve adjustorprovided with: an aperture region, which is fitted for sliding movementonto a part of the plunger, the part being located between a valve bodyof the main regulating valve and a valve body of the subsidiaryregulating valve, and a valve seat of the subsidiary regulating valve.5. A pressure regulator as defined in claim 1 wherein the pressureregulator further comprises a valve closing spring, which urges theplunger toward a direction of closing of the main regulating valve.
 6. Apressure regulator as defined in claim 1 wherein the gas having theregulated pressure within the pressure regulating chamber passes througha secondary gas flow path extending through a center area of the plungerand thus communicates with the gas discharging port.
 7. A pressureregulator as defined in claim 1 wherein either one of a valve body and avalve seat of the main regulating valve comprises an elastic body,either one of a valve body and a valve seat of the subsidiary regulatingvalve comprises an elastic body, and each of the elastic body of themain regulating valve and the elastic body of the subsidiary regulatingvalve is located in a state in which the elastic body is controlled suchthat the elastic body is prevented from deforming with respect todirections of valve opening and closing movements.
 8. A pressureregulator as defined in claim 7 wherein each of the elastic body of themain regulating valve and the elastic body of the subsidiary regulatingvalve is constituted of an O-ring.
 9. A pressure regulator as defined inclaim 8 wherein the pressure regulator is used for stabilization of fuelsupply to solid oxide type fuel cells and solid polymer type fuel cells.10. A pressure regulator, comprising: i) a gas introducing port, throughwhich a high-pressure gas having an unregulated pressure is introducedinto the pressure regulator, ii) a main regulating valve, which performsgas pressure reduction to a regulated pressure, a pressure lossoccurring at the main regulating valve, iii) a pressure regulatingchamber for relaxing pressure vibration of the gas, which has passedthrough the main regulating valve, iv) a diaphragm, which partitions offthe pressure regulating chamber and an atmospheric chamber from eachother, and which receives the regulated pressure within the pressureregulating chamber and is thereby displaced, v) a plunger, whichinterlocks the diaphragm and the main regulating valve with each other,vi) a pressure setting section for adjusting a quantity of thedisplacement of the diaphragm, vii) a gas discharging port, throughwhich the gas having the regulated pressure is discharged from thepressure regulator, and viii) a preliminary regulating valve, whichoperates by being interlocked with the main regulating valve through theplunger and which reduces the unregulated pressure of the high-pressuregas from the gas introducing port at a stage prior to the mainregulating valve, a pressure loss occurring at the preliminaryregulating valve, the gas, which has a pressure having thus been reducedby the preliminary regulating valve, being allowed to flow to the mainregulating valve.
 11. A pressure regulator as defined in claim 10wherein a valve body of the main regulating valve and a valve body ofthe preliminary regulating valve are located on the plunger, and thevalve body of the preliminary regulating valve is located on the gasintroducing port side.
 12. A pressure regulator as defined in claim 10wherein the pressure regulator further comprises adjustment means, whichis capable of adjusting a value of the pressure loss occurring at thepreliminary regulating valve.
 13. A pressure regulator as defined inclaim 12 wherein the adjustment means is capable of adjusting the valueof the pressure loss, which occurs at the preliminary regulating valve,with an operation for varying a position of a valve seat of thepreliminary regulating valve with respect to a movement of the plunger.14. A pressure regulator as defined in claim 12 wherein the adjustmentmeans is constituted of an adjustor provided with: an aperture region,which is fitted for sliding movement onto a part of the plunger, thepart being located between a valve body of the main regulating valve anda valve body of the preliminary regulating valve, and a valve seat ofthe preliminary regulating valve.
 15. A pressure regulator as defined inclaim 10 wherein either one of a valve body and a valve seat of the mainregulating valve comprises an elastic body, either one of a valve bodyand a valve seat of the preliminary regulating valve comprises anelastic body, and each of the elastic body of the main regulating valveand the elastic body of the preliminary regulating valve is located in astate in which the elastic body is controlled such that a direction ofswelling deformation of the elastic body becomes different fromdirections of valve opening and closing operations.
 16. A pressureregulator as defined in claim 15 wherein each of the elastic body of themain regulating valve and the elastic body of the preliminary regulatingvalve is constituted of an O-ring.
 17. A pressure regulator as definedin claim 10 wherein each of the plunger, which links the main regulatingvalve and the preliminary regulating valve with the diaphragm, and asupporter, which receives a pressure setting load acting upon thediaphragm, is constituted of a material selected from the groupconsisting of a light metal or a light metal alloy, such as aluminum orduralumin; a polyamide, a polyacetal, a polybutylene terephthalate, or apolypropylene, which is a crystalline resin; and an acetal, apolycarbonate, or acrylonitrile-butadiene-styrene-, which is anon-crystalline resin, the non-crystalline resin having a surface coatedwith an epoxy resin or a polyamide resin.
 18. A pressure regulator asdefined in claim 10 wherein a casing in which the diaphragm is locatedis constituted of a material selected from the group consisting of apolyamide, a polyacetal, a polybutylene terephthalate, or apolypropylene, which is a crystalline resin; and an acetal, apolycarbonate, or acrylonitrile-butadiene-styrene, which is anon-crystalline resin, the non-crystalline resin having a surface coatedwith an epoxy resin or a polyamide resin.
 19. A pressure regulator asdefined in claim 18 wherein the casing in which the diaphragm is locatedis constituted of the polyamide, the polyacetal, the polybutyleneterephthalate, or the polypropylene, which is the crystalline resin, andthe casing is formed with ultrasonic fusion bonding.
 20. A pressureregulator as defined in claim 19 wherein the pressure regulator is usedfor stabilization of fuel supply to solid oxide type fuel cells andsolid polymer type fuel cells.